Photoelectrochemical (PEC) water splitting to produce solar fuel (hydrogen) has long been considered as the Holy Grail to a carbon-free hydrogen economy. The PEC concept to produce solar fuel is to emulate the natural photosynthesis using man made materials. The bottle-neck in realising the concept practically has been the difficulty in identifying stable low-cost semiconductors that meet the thermodynamic and kinetic criteria for photoelectrolysis. We have fabricated a novel p-type LaFeO3 photoelectrode using an inexpensive and scalable spray pyrolysis method. Our nanostructured LaFeO3 photoelectrode results in spontaneous hydrogen evolution from water without any external bias applied. Moreover, the photoelectrode has a faradaic efficiency of 30% and showed excellent stability over 21 hours. From optical and impedance data, the constructed band diagram showed that LaFeO3 can straddle the water redox potential with the conduction band at-1.11 V above the reduction potential of hydrogen. We have fabricated a low cost LaFeO3 photoelectrode that can spontaneously produce hydrogen from water using sunlight, making it a strong future candidate for renewable hydrogen generation.

Density functional theory study has been carried out to design a new All-Solid-State dye-sensitized solar cell (SDSC), by applying a donor-acceptor conjugated polymer instead of liquid electrolyte. The typical redox mediator (I1−/I3−) is replaced with a narrow band gap, hole transporting material (HTM). The electronic and optical properties predict that donor and acceptor moieties in the polymeric body have increased the visible light absorption and charge transporting ability, compared to their parent polymers. A unique “upstairs” like band energy diagram is created by packing N3 between HTM and TiO2. Upon light irradiation on the proposed configuration, electrons will move from the dye to TiO2and from HTM to dye (to regenerate dye), simultaneously. Our theoretical simulations prove that the proposed configuration will be highly efficient as the HOMO level of HTM is 1.19 eV above the HOMO of sanitizer (dye); providing an efficient pathway for charge transfer. High short-circuit current density and power conversion efficiency is promised from the strong overlapping of molecular orbitals of HTM and sensitizer. A low reorganization energy of 0.21 eV and exciton binding energy of 0.55 eV, confirm the high efficiency of HTM. Finally, a theoretical open-circuit voltage of 1.49 eV would results high quantum yield while, the chemical stability of HTM towards oxidation can be estimated from its high ionization potential value (4.57 eV).

Recently, polymeric carbon nitride (g-C3 N4 ) as a proficient photo-catalyst has been effectively employed in photocatalysis for energy conversion, storage, and pollutants degradation due to its low cost, robustness, and environmentally friendly nature. The critical review summarized the recent development, fundamentals, nanostructures design, advantages, and challenges of g-C3 N4 (CN), as potential future photoactive material. The review also discusses the latest information on the improvement of CN-based heterojunctions including Type-II, Z-scheme, metal/CN Schottky junctions, noble metal@CN, graphene@CN, carbon nanotubes (CNTs)@CN, metal-organic frameworks (MOFs)/CN, layered double hydroxides (LDH)/CN heterojunctions and CN-based heterostructures for H2 production from H2 O, CO2 conversion and pollutants degradation in detail. The optical absorption, electronic behavior, charge separation and transfer, and bandgap alignment of CN-based heterojunctions are discussed elaborately. The correlations between CN-based heterostructures and photocatalytic activities are described excessively. Besides, the prospects of CN-based heterostructures for energy production, storage, and pollutants degradation are discussed.

Photocatalysis is a classical solution to energy conversion and environmental pollution control problems. In photocatalysis, the development and exploration of new visible light catalysts and their synthesis and modification strategies are crucial. It is also essential to understand the mechanism of these reactions in the various reaction media. Recently, bismuth and graphene’s unique geometrical and electronic properties have attracted considerable attention in photocatalysis. This review summarizes bismuth-graphene nanohybrids’ synthetic processes with various design considerations, fundamental mechanisms of action, heterogeneous photocatalysis, benefits, and challenges. Some key applications in energy conversion and environmental pollution control are discussed, such as CO2 reduction, water splitting, pollutant degradation, disinfection, and organic transformations. The detailed perspective of bismuth-graphene nanohybrids’ applications in various research fields presented herein should be of equal interest to academic and industrial scientists.

Electrochemical CO2 reduction reaction (CO2RR) provides a promising approach to curbing harmful emissions contributing to global warming. However, several challenges hinder the commercialization of this technology, including high overpotentials, electrode instability, and low Faradic efficiencies of desirable products. Several materials have been developed to overcome these challenges. This mini-review discusses the recent performance of various cobalt (Co) electrocatalysts, including Co-single atom, Co-multi metals, Co-complexes, Co-based metal–organic frameworks (MOFs), Co-based covalent organic frameworks (COFs), Co-nitrides, and Co-oxides. These materials are reviewed with respect to their stability of facilitating CO2 conversion to valuable products, and a summary of the current literature is highlighted, along with future perspectives for the development of efficient CO2RR.

A photoelectrochemical (PEC) water splitting ability of pure ZnO and manganese-incorporated ZnO thin films fabricated via a simple aerosol-assisted chemical vapour deposition (AACVD) method was compared in Na2SO4 electrolyte solution. Optical properties analysis showed the shifting of optical band gap from 3.02 to 2.76 eV as the molar ratio of Mn varies from 0.02 to 0.15. All the compositions of Zn1−xMnxO (x = 0.02 to 0.15) show superior photocurrent density compared to pure ZnO-based photoanodes. The activity of Zn0.85Mn0.15O was found highest with photocurrent density of 3.81 mA/cm2. This activity enhancement was due to the shifting of the optical band gap in the visible region with the increase in absorption intensity. Moreover, the activity is further affected by the growth of uniform and homogeneous structures onto the photoanodes. The morphology of the films and size of crystallites change by varying amounts of Mn into the ZnO films. Overall, this work demonstrates that Zn1−xMnxO has a significant potential for PEC water splitting with further tailoring of their electronic properties.

High temperature and overheating of photovoltaic panels lead to efficiency losses and eventual degradation. For solar PV systems, this is a significant impediment for achieving economic viability. In this study, a novel Window-Integrated Concentrated Photovoltaic (WICPV) system is proposed for window integration. This offers high (50%) transparency and is fabricated and characterised indoors at an irradiance of 1000 Wm−2. Its electrical performance is tested (a) without applied cooling (i.e. under natural ventilation) and (b) with a heat sink to accommodate passive cooling media. The results are compared to study the effects of reduction in operating temperature on system performances. The effectiveness of a sensible cooling medium (water) and two latent heat removal media, phase change materials (or PCMs, RT50 and RT28HC), is investigated. This paper reports the passive temperature regulation of this WICPV at ambient testing conditions. The results demonstrate an increase in electrical power output by (i) 17% (RT28HC), (ii) 19% (RT50), and (iii) 25 % (circulating water) compared with the naturally ventilated system. This shows that PCMs are considerably useful for thermal regulation of the WICPV. Any improvement in efficiencies will be beneficial for increasing electrical energy generation and reducing peak energy demands.

Gold nanoparticles (Au NPs) play a significant role in science and technology because of their unique size, shape, properties and broad range of potential applications. This review focuses on the various approaches employed for the synthesis, modification and functionalization of nanostructured Au. The potential catalytic applications and their enhancement upon modification of Au nanostructures have also been discussed in detail. The present analysis also offers brief summaries of the major Au nanomaterials synthetic procedures, such as hydrothermal, solvothermal, sol-gel, direct oxidation, chemical vapor deposition, sonochemical deposition, electrochemical deposition, microwave and laser pyrolysis. Among the various strategies used for improving the catalytic performance of nanostructured Au, the modification and functionalization of nanostructured Au produced better results. Therefore, various synthesis, modification and functionalization methods employed for better catalytic outcomes of nanostructured Au have been summarized in this review.

3D porous, thin sheet-like rGO aerogel was fabricated to explore its antimony (Sb) removal potential from wastewater. Langmuir isothermal and pseudo-second-order kinetic model best-suited the adsorption process. The maximum adsorption capacities were 168.59 and 206.72 mg/g for Sb (III and V) at pH 6.0 respectively. The thermodynamic parameters designated the process to be thermodynamically spontaneous, endothermic reaction, a result of dissociative chemisorption. The rGO aerogel bestowed good selectively among competing ions and reusability with 95% efficiency. rGO posed excellent practicability with Sb-spiked tap water and fixed-bed column experiments showing 97.6% of Sb (III) (3.6 μg/L) and 96.8% of Sb (V) (4.7 μg/L) removal from tap water and from fixed column bed experiments breakthrough volumes (BV) for the Sb (III) and Sb (V) ions were noted to be 540 BV and 925 BV respectively, until 5 ppb, which are below the requirement of MCL for Sb in drinking water (6 μg/L). XPS and DFT analyses explained adsorption mechanism and depicted a higher affinity of Sb (V) towards rGO surface than Sb (III).

Covalent organic frameworks (COFs) are emerging crystalline polymeric materials with highly ordered intrinsic and uniform pores. Their synthesis involves reticular chemistry, which offers the freedom of choosing building precursors from a large bank with distinct geometries and functionalities. The pore sizes of COFs, as well as their geometry and functionalities, can be pre-designed, giving them an immense opportunity in various fields. In this mini-review, we will focus on the use of COFs in the removal of environmentally hazardous metal ions and chemicals through adsorption and separation. The review will introduce basic aspects of COFs and their advantages over other purification materials. Various fabrication strategies of COFs will be introduced in relation to the separation field. Finally, the challenges of COFs and their future perspectives in this field will be briefly outlined.

Low concentrating photovoltaic (LCPV) system has been studied extensively, which showed excellent potential for the building integration application. However, such a system suffers from higher operating temperatures due to the concentrated light exposed into the solar cell. In this work, two different methods have been used to regulate the operating temperature of the solar cell without the interference of any other external mechanism. Two concepts were used to study the operating temperature of the solar cells are: i) use of Argon gas within the concentrator element, ii) incorporation of polymer-dispersed liquid crystal films (PDLC) on top of the module. In both cases, the power was improved by 37 mW–47 mW when temperature was reduced by 10 °C and 4 °C for the Argon gas-filled module and PDLC integrated module, respectively. In addition, the temperature effect of the PDLC integrated module showed a unique nature of reduction of the short circuit current due to the orientation of the liquid crystal particle, which increased at a higher temperature. The current study, therefore, shows the greater potential of improving the operating efficiency and reduction of solar cell temperature, without the need for additional pumping power such as needed for photovoltaic thermal application.

A molecular cross-linking approach of the perovskite grains combined with amine-based surface passivation leads to hysteresis-free perovskite transistors.

Dye-sensitized solar cells based on a poly(styrene-co-acrylonitrile) based gel electrolyte gave a photo conversion efficiency of 6.72%.

Herein, we report the synthesis of Cr incorporated ZnO sheets arrays microstructures and construction of photoelectrode through a direct aerosol assisted chemical vapour deposition (AACVD) method. The as-prepared Cr incorporated ZnO microstructures were characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray spectroscopy, X-ray photoelectron spectroscopy and UV-Vis diffused reflectance spectroscopy. The Cr incorporation in ZnO red shifted the optical band gap of as-prepared photoanodes. The 15% Cr incorporation in ZnO has shown enhanced PEC performance. The AACVD method provides an efficient in situ incorporation approach for the manipulation of morphological aspects, phase purity, and band structure of photoelectrodes for an enhanced PEC performance.

A typical Z-scheme system is composed of two photocatalysts which generate two sets of charge carriers and split water into H2 and O2 at different locations. Scientists are struggling to enhance the efficiencies of these systems by maximizing their light absorption, engineering more stable redox couples, and discovering new O2 and H2 evolutions co-catalysts. In this work, Au decorated WO3/g-C3N4 Z-scheme nanocomposites are fabricated via wet-chemical and photo-deposition methods. The nanocomposites are utilized in photocatalysis for H2 production and 2,4-dichlorophenol (2,4-DCP) degradation. It is investigated that the optimized 4Au/6% WO3/CN nanocomposite is highly efficient for production of 69.9 and 307.3 µmol h−1 g−1 H2 gas, respectively, under visible-light (λ > 420 nm) and UV–visible illumination. Further, the fabricated 4Au/6% WO3/CN nanocomposite is significant (i.e. 100% degradation in 2 h) for 2,4-DCP degradation under visible light and highly stable in photocatalysis. A significant 4.17% quantum efficiency is recorded for H2 production at wavelength 420 nm. This enhanced performance is attributed to the improved charge separation and the surface plasmon resonance effect of Au nanoparticles. Solid-state density functional theory simulations are performed to countercheck and validate our experimental data. Positive surface formation energy, high charge transfer, and strong non-bonding interaction via electrostatic forces confirm the stability of 4Au/6% WO3/CN interface.

Heterogeneous photocatalysis, employing semiconductor metal oxides, especially at nano scale is a promising technique to mortify the dye residues from effluent. The photocatalysts on doping with a suitable dopant can be modified to enhance the photocatalytic activity. In this study, undoped and series of Fe3+ doped ZnO have been grown on polyester fabric through low temperature hydrothermal method to generate photocatalytic membrane reactors (PMRs). The material grown on the surface of fabric was characterized by XRD, EDX, SEM, TEM, STEM, AFM, XPS, ICP-MS, DRS and PL studies. For ZnO/PMR and Fe3+@ZnO/PMR photocatalytic activity was determined and examined to increase for Fe3+@ZnO/PMR in the solar region due to the reduction of band gap from 3.2 to 2.6 eV on Fe3+doping. The surface properties of PMRs were also determined by zeta potential and contact angle. The characterized ZnO and Fe3+@ZnO nano discs based PMRs have been used to degrade RB5 reactive dye on irradiating with artificial sunlight (D65, 72 W). The reaction parameters i.e. initial dye and oxidant concentration, pH and irradiation time have been optimized by Response Surface Methodology (RSM). The extent of dye degradation has been evaluated by UV/vis spectroscopy and FTIR. The maximum degradation achieved was 88.89% for ZnO/PMR and 98.34% for Fe3+@ZnO PMR in 180 min. The photocatalytic efficiency of Fe3+@ZnO PMR was investigated for 15 batches, with a slight gradual decrease in activity after eight batches.

The increase in carbon dioxide (CO2) concentration in the atmosphere raises earth's temperature. CO2 emissions are closely related to human induced activities such as burning of fossil fuels and deforestation. So, to make the environment sustainable, carbon capture and storage (CCS) is required to reduce CO2 emissions. In this study, CO2 hydrate (CO2:6H2O) formation has been explored as an approach to capture CO2 in the integrated gasification combined cycle (IGCC) conditions. The formation of hydrate was experimentally investigated in an isochoric system with high-pressure volumetric analyzer (HPVA). The solubility of CO2 in water using experimental pressure–time (P-t) curves were analyzed to determine the formation of hydrate. Additionally, the effect of newly synthesized combined promoters and various driving forces were evaluated. The experimental results demonstrated that the CO2 uptake expanded as ΔP expanded and designated combined promoters type T1-5 and type T3-2 were the two best, acquiring a uptake of 5.95 and 5.57 mmol of CO2 per g of H2O separately. Ethylene glycol mono-ethyl ether (EGME) was demonstrated to be a good option to THF when linked with SDS, with a CO2 uptake of 5.45 mmol for the designated combined promoters T1A-2. Additionally, the total sum of CO2 devoured through hydrate development maximize as the measure of water inside mesoporous silica increased. All results of the studied parameters confirmed the reliability of experiments and successful implementation.

Transition metal ion incorporation has been emerged as an effective stratagem to enhance the performance of metal oxide photoanodes. In the present work, we design and fabricate the plain ZnO and (2, 5, 10 and 15%) Fe incorporated ZnO photoanodes by aerosol assisted chemical vapor deposition (AACVD) method. The 15% Fe incorporated ZnO photoanode displayed excellent photocurrent density of 4.6 mA/cm2 at 0.7 VAg/AgCl with photo conversion efficiency of 2.4%, which is 159 times higher than pure ZnO photoanode (0.028 mA/cm2). The obtained results are remarkably superior to the previous results. Furthermore, the Fe incorporated photoelectrodes have also shown good stability. The excellent photoelectrochemical performance of Fe incorporated ZnO showed red shift in band edge with relative decrease in the band gap energy compared to pure ZnO. The demonstration of this simple method for the deposition of Fe incorporated ZnO to fabricate highly efficient photoanode for the PEC water splitting can easily be applied to other similar systems.

The development of low-cost, durable and efficient photocatalyst for overall photoelectrochemical water splitting is in demand to overcome the renewable energy crises. Herein, we demonstrate the efficient photoelectrochemical water splitting by cobalt (Co) incorporated zinc oxide (Zn1-xCoxO) thin films deposited via aerosol assisted chemical vapour deposition (AACVD) technique. The as-deposited Co incorporated ZnO thin films were characterised by powdered X-ray diffraction (pXRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and ultra violet-visible spectroscopy (UV-Vis). These films with different concentration of cobalt were investigated for water splitting applications and the best results were achieved for the films with 15% Co incorporation.

Solar energy is a large, exploitable, renewable resource where it can supply the earth with enough energy in one hour, equivalent to the mankind’s total energy consumption in a year. Nanomaterials, for semiconductor material, used as a photocatalyst to convert sunlight into chemical fuel (hydrogen) via photoelectrochemical water splitting process, has been considered as the Holy Grail to a carbon free hydrogen economy. Conversion of sunlight into hydrogen is a promising, clean and sustainable way of generating hydrogen.

In this research project we have designed, synthesised, characterised and tested new materials for which can generate hydrogen from water using solar energy. Due to the lack of suitable p-type semiconductor materials, this work has focused on synthesising and developing new, stable, visible light active photocathodes for solar hydrogen generation.

In pursuit of this stable photocathode, we have synthesised stable visible light active LaFeO₃ which has shown some promise as a future candidate p-type photocathode. This was produced by cheap, novel and scalable spray pyrolysis technique which has resulted in current densities of 0.16 mA cm⁻² at 0.26 V vs RHE and shown stability over 21 hours. Subsequently, this led to hydrogen generation of 0.18 μmol cm⁻². Furthermore, LaFeO₃-Ag and LaFeO₃-Ni were fabricated by spin coating silver and nickel nanoparticles on to the spray pyrolysed LaFeO₃, to enhance photocurrent density for enhance hydrogen generation via solar water splitting. This led to over double the amount of hydrogen being produced. Similarly, TaFeO₄ was fabricated by sol-gel method which yielded 0.091 μmol g⁻¹ of hydrogen. Future work is required on TaFeO₄ to fabricate electrode form of the material so its band structure many be determined. This may be done by microwave assisted annealing.

In recent years as a larger proportion of our energy needs are being met by renewable energy sources, research and development in energy storage is becoming more significant. Oxygen electrodes, found in electrical energy storage applications such as fuel cells, water electrolysers and metal-air secondary batteries, face the demand for improved performance. In view of this, the research in this thesis focuses on the synthesis and development of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts to overcome the slow kinetics of the oxygen electrochemical reactions in alkaline media, followed by the investigation of their combined performance in a tri-electrode zinc-air secondary cell. The ORR performance of various transition metal oxides and carbonaceous materials was initially compared against benchmark catalyst Pt/C using rotating disc electrode measurements. Amorphous MnOx combined with Vulcan XC-72R was found to demonstrate high ORR activity and good stability over the range of cathodic current densities tested. The influence of the synthesis parameters of amorphous MnOx on its ORR activity was subsequently investigated and it was found that optimal amorphous MnOx catalyst can be synthesised with a molar ratio of MnO4-/ Mn2+ of 2.67, by adding KMnO4 to Mn(CH3COO)2 in a basic solution of pH 12 at 295 K. Similarly, the OER performance of transition metal oxides and hydroxides coated on metal mesh was compared and electrodeposited Ni-Fe hydroxide was reported to display high activity and durability when held at anodic potentials. Based on this, various compositions of Ni-based binary and Ni-Fe based ternary metal hydroxides were screened with a unique microelectrode set-up at high current densities up to 1 a cm-2. Ni-Fe-Co hydroxide showed most improved OER performance. The effect of electrodeposition parameters on the electrocatalytic performance of Ni-Fe-Co hydroxide were examined and used to further optimise the catalyst. Ni-Fe-Co hydroxide cathodically deposited at 300 mA cm-2 for 240 s at 22 ºC, pH 3.9 was found to demonstrate best OER performance, giving an overpotential of 235 mV at 0.1 a cm-2. The electrodes with optimised catalysts were tested in an in-house built zinc-air cycling set-up, demonstrating energy efficiencies of 58-61% up to 40 h at 20 mA cm-2 in 4 M NaOH + 0.3 M ZnO at 333 K.

Platinum-free counter electrodes are crucial for developing cost effective solar energy harvesting technology. We describe here the fabrication of efficient platinum free FTO counter electrodes for dye sensitized solar cells based on pristine polyaniline, polyaniline doped with sulfuric acid, ammonuim lauryl sulfate, as well as binary doped with sulfuric acid and ammonium lauryl sulphate. The characteristics of these counter electrodes were analyzed using cyclic voltammetry, photocurrent density–voltage and electrochemical impedance spectroscopy measurements. At optimized fabrication conditions, the counter electrode shows significantly high photoelectric conversion efficiency of 4.54% compared to 4.03% for reference platinum counter electrode. Charge transfer resistance at the interface between electrolyte and counter-electrode is also decreased for the optimized polyaniline based counter electrode. Furthermore, the device presented characteristics of multiple start/stop ability and fast activity. The simple preparation procedure, low cost and improved photoelectric properties permit fabricated counter electrode to be a reliable alternative for dye sensitized solar cells.

Concentrating Photovoltaic technology is considered now as a promising option for solar electricity generation along with the conventional flat plate PV technology especially in high direct normal irradiance areas. However, the concentrating photovoltaic industry sector still struggles to gain market share and to achieve adequate economic returns due to challenges such as the high temperature of the solar cell which causes a reduction its efficiency.
The work presented in this thesis is targeted to influence the overall performance of a high concentrated photovoltaic system by integrating both the multi-layered microchannel heat sink technique and a phase change material storage system. The proposed integrated system is composed of a multi-layered microchannel heat sink attached to a single solar cell high concentrated photovoltaic module for thermal regulation purposes. This is expected to reduce the solar cell temperature hence increasing the electrical output power. The high concentrated photovoltaic and multi-layered microchannel heat sink system is then connected to a phase change material thermal storage system to store efficiently the thermal energy discharged by the high concentrated photovoltaic and multi-layered microchannel heat sink system.
The first part of the thesis discusses the influence of the multi-layered microchannel heat sink on the high concentrated photovoltaic module using both the numerical and experimental approaches. The multi-layered microchannel heat sink has been integrated for the first time with the single cell receiver and tested successfully. A numerical analysis of the high concentrated photovoltaic and multi-layered microchannel heat sink system shows the potential of the heat sink to reduce the solar cell maximum temperature and its uniformity.
The thermal behaviour of the multi-layered microchannel heat sink under non-uniform heat source was experimentally investigated. The results show that in extreme heating load of 30W/cm² and in heat transfer fluid flow rate of 30ml/min, increasing the number of layers from 1-layer to 4-layers reduced the heat source temperature from 88.55°C to 73.57°C, respectively. In addition, the single layer multi-layered microchannel heat sink suffers of the most heat source temperature non-uniform compared to the heat sinks with higher number of layers. Also, the results show that increasing the number of layers from 1-layer to 4-layers reduced the pressure drop from 16.6mm H2O to 3.34 mm H2O.
The indoor characterization of the high concentrated photovoltaic and multi-layered microchannel heat sink system investigated the effect of the number of layers, the homogeniser materials, and the heat transfer fluid flow rate and inlet temperature on the electrical and thermal performance of the system. The results show that the maximum power of the high concentrated photovoltaic module with glass homogeniser is 3.46W compared to 2.49W when using the crystal resin homogeniser for the 2-layers multi-layered microchannel heat sink and 30ml/min under 1000W/m² irradiance intensity. Increasing the number of layers from 1-layer to 3-layers on the high concentrated photovoltaic and multi-layered microchannel heat sink system increased the maximum electrical power by 10% and decreased the solar cell temperature 3.15°C for the heat transfer fluid flow rate of 30ml/min. This gives an increase in the maximum electrical power of 98.4mW/°C.
The outdoor characterisation of the high concentrated photovoltaic and multi-layered microchannel heat sink system performance was evaluated at the University of Exeter, Penryn Campus, UK. The achieved maximum output electrical power of the system was 4.59W, filling factor of 75.1%, short circuit current of 1.96A and extracted heat of 12.84W which represents of 74.9% of the maximum solar irradiance of 881W/m². In addition, the maximum solar cell temperature reached to 60.25°C.
Secondly, the experimental studies were carried out in order to investigate the performance of the phase change material storage system using paraffin wax as the PCM materials. The thermal storage system performance was evaluated in various conditions. The results show that inclination of the phase change material storage influences the melting behaviour of the phase change material where the phase change material storage of 45º inclination position melts faster than the phase change material storages in the 0º and 90º inclination positions. The phase change material melting time is reduced in the PCM storage of 45º inclination position by 13% compared to the 0º inclination position.
The last part of the thesis discusses the integration of the phase change material storage with the high concentrated photovoltaic and multi-layered microchannel heat sink system. A 3D numerical model was developed to predict the behaviour of the integrated high concentrated photovoltaic and multi-layered microchannel heat sink system with the phase change material storage system using variable source conditions. The results show a higher heat absorption rate on phase change material storage that uses a lower melting temperature phase change material compared to the higher phase change material melting temperature. The multi-stages storage with different phase change materials melting temperature showed a lower heat absorption compared to the phase change material arrangement with the lower melting temperature. Also, the rate of the absorbed heat fluctuation is less affected by the phase change material arrangement with higher melting temperature.

Visible light active semiconductor Bi 2 WO 6 photoelectrodes with desired physical and chemical properties are sought for solar energy conversion and photocatalytic applications. The porous nanostructured Bi 2 WO 6 photoelectrodes are prepared by Spray Pyrolysis (SP). A detail study has been conducted to correlate the annealing temperature, morphology and crystallographic orientation with the photoelectrochemical (PEC), electrochemical and photocatalytic properties. The photoelectrodes possess an optical bandgap of 2.82 eV and exhibit anodic photocurrent. The current-voltage characterization of Bi 2 WO 6 photoelectrodes reveals that the photocurrent density and photocurrent onset potential is strongly dependent on the deposition parameters. The PEC study shows that the photoelectrode annealed at 525 °C has photocurrent density of 42 μAcm −2 at 0.23 V (vs Ag/AgCl/3M KCl) under AM1.5 illumination and exhibit superior photocatalytic activity for Rhodamine B (RhB) degradation. The electrochemical study shows that the photoelectrode has flatband potential of 2.85 V which is in good agreement with photocurrent onset potential. This finding will have a significant influence on further exploitation of Bi 2 WO 6 as a potential semiconductor material in solar energy conversion and photocatalytic applications.

Nanostructured Bi2WO6 thin film electrodes with enhanced solar energy conversion and photocatalytic properties have been fabricated using Aerosol-Assisted Chemical Vapor Deposition (AACVD). By conveniently controlling the deposition process parameters, Bi2WO6 electrodes were fabricated with nanoplates and hierarchical buckyball-shaped microsphere structures morphology. A detailed study has been conducted to correlate the structure and morphology with the photoelectrochemical (PEC) and photocatalytic dye degradation performance. The PEC investigations revealed that the hierarchical buckyball-shaped microsphere structured Bi2WO6 electrodes have shown the photocurrent density of 220 μAcm-2 while nanoplates have a photocurrent density of 170 μAcm-2 at 0.23 V (vs. Ag/AgCl/3M KCl) under AM1.5 illumination. The PEC characterization of Bi2WO6 electrodes also reveals that the photocurrent density and photocurrent onset potential is strongly dependent on the orientation and morphology, hence the deposition parameters. Similarly, the methylene blue (MB) and rhodamine B (RhB) photodegradation performance of Bi2WO6 electrodes also show a strong correlation with morphology. This finding provides an appropriate route to engineer the energetic and interfacial properties of Bi2WO6 electrode to enhance solar energy conversion and the photocatalytic performance of semiconductor materials.

The use of nanomaterials in solar energy conversion and photocatalytic degradation of environmental pollutants represents an opportunity to improve the performance, density, and ease of transportation in renewable resources. Among renewables resources, solar energy is considered as the largest exploitable resource, supplying the earth with energy in 1 hour equivalent to mankind’s total energy consumption in an entire year. Collecting and storing sunlight in chemical bonds (solar fuel) using photoelectrochemical water splitting (PEC) is a promising, a clean and sustainable way for hydrogen generation. Moreover, the photocatalytic process has great potential and high efficiency for removal of organic pollutants from water under direct natural sunlight irradiation. The aim of this project is to design, fabricate, characterize and performance enhancement of novel semiconductor materials that could efficiently harvest and store solar energy by splitting water to produce hydrogen and to perform dye degradation as well. The lack of suitable p-type photocathode has been considered and the focus of this work was to design and develop the new stable visible light absorbing photocathode materials.
. In pursuit of the stable photocathode, in this work YFeO3, which is a cheap and abundant material, with promising properties, and so was chosen as the photocathode in the development of the PEC cell. YFeO3 thin films were produced by spray pyrolysis technique onto fluorine-doped tin oxide film on glass. Results showed that YFeO3 photoelectrode has achieved a photocurrent of 0.6 mA cm-2 at 0.5 V vs. RHE and maximum of 0.41 μmol/cm2 of hydrogen has obtained as well.
. Similarly, to look for suitable and cheap materials for environmental remediation, Bi2WO6 thin films were produced by spray pyrolysis and aerosol-assisted chemical vapour deposition techniques. Results showed that the nanostructure and texture of the films can be controlled by controlling the deposition parameters. Moreover, photocatalytic degradation of rhodamine B (RhB) and methylene blue (MB) dyes have been successfully achieved.
. Finally, α-Fe2O3 films were fabricated as counter electrodes for dye-sensitized solar cells in order to compete for platinum counter electrode. These films were fabricated using aerosol-assisted chemical vapour deposition and spray pyrolysis techniques. The results showed that the performance of the samples prepared by aerosol-assisted chemical vapour deposition as a counter electrodes is higher than of the samples prepared by spray pyrolysis.

Porous ZnO/C nanocomposites derived from 3 different Zinc based metal-organic frameworks (MOFs) including MOF-5, MOF-74 and ZIF-8, were prepared at high temperature under water-steam atmosphere and their performances in photocatalytic H 2 evolution reaction (HER) and photodegradation of organic dye pollutants were evaluated. The formation mechanism from MOF precursors, the structural properties, morphologies, compositions and textural properties of the derived ZnO/C composites were fully investigated based on different characterization techniques and the correlation between the precursors and the derived composites was discussed. It is evident that MOF precursors determine the crystalline structures, doping profiles, thermal stabilities and metal oxide-carbon weight percentage ratios of the resulting composites. The correlation between MOFs and their derived nanocomposites indicates that different parameters play unalike roles in photocatalytic performances. The desired properties can be tuned by selecting appropriate MOF precursors. MOF-5 derived porous ZnO/C nanocomposite not only exhibits the highest photocatalytic dye degradation activity under visible light among these MOFs, but also outperforms those derived from MOF-74 and ZIF-8 up to 9 and 4 times in photocatalytic HER respectively. This study offers simple and environmentally friendly approaches to further develop new homogeneously dispersed functional metal oxide/carbon composites for various energy and environment-related applications.

In the present work, 10 to 14 nm titania nanoparticles with high-packing density are synthesized by the soft-template method using a range of cationic surfactants including cetyl trimethylammonium bromide (CTAB), Sodium dodecyl sulfate (SDS), and dodecyl trimethylammonium bromide (DTAB). The synthesized nanoparticles are used as a photoanode material in dye solar cells. Density functional theory (DFT) simulations reproduce our experimental results of charge transfer and strong interaction between the TiO2 and N719. N719-TiO2 complex establishes strong electrostatic bonding through H of the dye with the O of TiO2 surface. Solar cell efficiency of 6.08% with 12.63 mA/cm2, 793 mV, and 48.5% for short circuit current density, open circuit voltage, and fill factor, respectively, are obtained under 1 sun illumination for the dye-sensitized solar cell (DSSC) using a film of mesoporous TiO2 synthesized from the SDS surfactant. On the other hand, the 21 nm commercial TiO2 powder (P25) device results in 4.60% efficiency under similar conditions. Electrochemical impedance spectroscopic studies show that the SDS device has lesser charge transport resistance than the other devices because of its higher surface area, packing density, and dye loading capacity. Our results show that employing high packing density-based TiO2 nanoparticles represents a commercially viable approach for highly beneficial photoanode development for future DSSC applications.

Since textile industry is the greatest consumer of water, it generates large quantities of effluents. The advanced methods of water treatment present a great potential in terms of wastewater reuse for irrigation. Heterogeneous photocatalysis is a promising technique to mortify the dye residues from textile effluent. In this study, Fe3+ doped ZnO has been synthesized through microwave assisted sol-gel method. The crystallinity and elemental composition of fabricated material was determined by X-ray diffraction (XRD). Two-dimensional disc shaped morphology of photocatalyst has been examined by scanning electron microscopy (SEM) of Fe+3 doped ZnO. Diffused reflectance spectroscopy confirmed its high photocatalytic activity in solar range on reduction of band gap from 3.2 to 2.8 eV after doping. The characterized Fe+3 doped ZnO samples have been used to degrade RB5 dye on irradiating with artificial sunlight (D65). The reaction parameters i.e. initial dye and oxidant concentration, pH and irradiation time have been optimized by Response surface methodology (RSM). The extant of dye degradation has been evaluated by UV/vis and FTIR spectroscopy. The maximum degradation up to 98.32 % in 3 h was achieved on using ZnO doped with 5 mM of Fe+3 under optimized conditions. The phytotoxicity of treated and untreated effluent on length of root and shoot of spinach in addition to yield was measured. The remarkable increase in vegetative growth of plants was observed on using treated textile effluent.

Recently, oxynitrides materials such as β-TaON has been using as a photoanode material in the field of photocatalysis and is found to be promising due to its suitable band gap and charge carrier mobility. Computational study of the crystalline β-TaON in the form of primitive unit cell, supercell and its N, Ta, and O terminated surfaces are carried out with the help of periodic density functional theory (DFT). Optical and electronic properties of all these different species are simulated, which predict TaON as the best candidate for photocatalytic water splitting contrast to their Ta2O5 and Ta3N5 counterparts. The calculated bandgap, valence band, and conduction band edge positions predict that β-TaON should be an efficient photoanodic material. The valence band is made up of N 2p orbitals with a minor contribution from O 2p, while the conduction band is made up of Ta 5d. Turning to thin films, the valence band maximum; VBM (−6.4 eV vs. vacuum) and the conduction band minimum; CBM (−3.3 eV vs. vacuum) of (010)-O terminated surface are respectively well below and above the redox potentials of water as required for photocatalysis. Charge carriers have smaller effective masses than in the (001)-N terminated film (VBM −5.8 and CBM −3.7 eV vs. vacuum). However, due to wide band gap (3.0 eV) of (010)-O terminated surface, it cannot absorb visible wavelengths. On the other hand, the (001)-N terminated TaON thin film has a smaller band gap in the visible region (2.1 eV) but the bands are not aligned to the redox potential of water. Possibly a mixed phase material would produce an efficient photoanode for solar water splitting, where one phase performs the oxidation and the other reduction.

BiVO4 is a considerably promising semiconductor for photoelectrochemical water splitting due to its stability, low cost and moderate band gap. In this research, g-C3N4 was proposed in Z-scheme configuration which boosted the performance of BiVO4 up to four times. The experimental observations were counterchecked with Density Functional Theory (DFT) simulations. A TiO2/BiVO4 heterojunction was developed and its performance was compared with that of g-C3N4/BiVO4. The photocurrent for g-C3N4/BiVO4 was 0.42 mAcm−2 at 1.23 V vs. RHE which was the highest among g-C3N4 based Z-scheme heterojunction devices. Lower charge transfer resistance, higher light absorption and more oxygen vacancy sites were observed for the g-C3N4 based heterojunction. The simulated results attested that g-C3N4 and BiVO4 formed a van der Waals type heterojunction, where an internal electric field facilitated the separation of electron/hole pair at g-C3N4/BiVO4 interface which further restrained the carrier recombination. Both the valence and conduction band edge positions of g-C3N4 and BiVO4 changed with the Fermi energy level. The resulted heterojunction had small effective masses of electrons (0.01 me) and holes (0.10 me) with ideal band edge positions where both CBM and VBM were well above and below the redox potential of water.

© 2018 Hydrogen Energy Publications LLC Plasmonic Ni nanoparticles were incorporated into LaFeO3 photocathode (LFO-Ni) to excite the surface plasmon resonances (SPR) for enhanced light harvesting for enhancing the photoelectrochemical (PEC) hydrogen evolution reaction. The nanostructured LFO photocathode was prepared by spray pyrolysis method and Ni nanoparticles were incorporated on to the photocathode by spin coating technique. The LFO-Ni photocathode demonstrated strong optical absorption and higher current density where the untreated LFO film exhibited a maximum photocurrent of 0.036 mA/cm2 at 0.6 V vs RHE, and when incorporating 2.84 mmol Ni nanoparticles the photocurrent density reached a maximum of 0.066 mA/cm2 at 0.6 V vs RHE due to the SPR effect. This subsequently led to enhanced hydrogen production, where more than double (2.64 times) the amount of hydrogen was generated compared to the untreated LFO photocathode. Ni nanoparticles were modelled using Finite Difference Time Domain (FDTD) analysis and the results showed optimal particle size in the range of 70–100 nm for Surface Plasmon Resonance (SPR) enhancement.

Photoelectrochemical (PEC) water splitting to produce solar fuel (hydrogen) has long been considered as the Holy Grail to a carbon-free hydrogen economy. The PEC concept to produce solar fuel is to emulate the natural photosynthesis using man made materials. The bottle-neck in realising the concept practically has been the difficulty in identifying stable low-cost semiconductors that meet the thermodynamic and kinetic criteria for photoelectrolysis. We have fabricated a novel p-type LaFeO3 photoelectrode using an inexpensive and scalable spray pyrolysis method. Our nanostructured LaFeO3 photoelectrode results in spontaneous hydrogen evolution from water without any external bias applied. Moreover, the photoelectrode has a faradaic efficiency of 30% and showed excellent stability over 21 hours. From optical and impedance data, the constructed band diagram showed that LaFeO3 can straddle the water redox potential with the conduction band at-1.11 V above the reduction potential of hydrogen. We have fabricated a low cost LaFeO3 photoelectrode that can spontaneously produce hydrogen from water using sunlight, making it a strong future candidate for renewable hydrogen generation.

Density functional theory study has been carried out to design a new All-Solid-State dye-sensitized solar cell (SDSC), by applying a donor-acceptor conjugated polymer instead of liquid electrolyte. The typical redox mediator (I1−/I3−) is replaced with a narrow band gap, hole transporting material (HTM). The electronic and optical properties predict that donor and acceptor moieties in the polymeric body have increased the visible light absorption and charge transporting ability, compared to their parent polymers. A unique “upstairs” like band energy diagram is created by packing N3 between HTM and TiO2. Upon light irradiation on the proposed configuration, electrons will move from the dye to TiO2and from HTM to dye (to regenerate dye), simultaneously. Our theoretical simulations prove that the proposed configuration will be highly efficient as the HOMO level of HTM is 1.19 eV above the HOMO of sanitizer (dye); providing an efficient pathway for charge transfer. High short-circuit current density and power conversion efficiency is promised from the strong overlapping of molecular orbitals of HTM and sensitizer. A low reorganization energy of 0.21 eV and exciton binding energy of 0.55 eV, confirm the high efficiency of HTM. Finally, a theoretical open-circuit voltage of 1.49 eV would results high quantum yield while, the chemical stability of HTM towards oxidation can be estimated from its high ionization potential value (4.57 eV).

Bimetallic chlorodi-/triorganotin(IV) derivatives of general formulas R2(H2O)SnLCSSSn(Cl)R2 (R=Me: 1; Ph: 2) and R3Sn(Na)LCSSSnR3·H2O (R=Bu: 3; Ph: 4) were prepared by reaction of iminodiacetic acid disodium salt hydrate (Na2LH) with CS2 and R2SnCl2/R3SnCl in methanol. The reaction between Na2LH, CS2, and PdCl2 produced [Na2LCSS]2Pd·2H2O (5) which was treated with R3SnCl to synthesize the heterobimetallic derivatives [R3Sn(Na)LCSS]2Pd·2H2O (R=Me: 6; Ph: 7). The complexes were characterized by microanalysis, spectroscopic, and thermogravimetric analyses. Elemental analysis data, mass fragmentation, and thermal degradation patterns supported the molecular composition of the complexes. FT-IR data indicated monodentate binding of carboxylate while a chelating coordination mode of the dithiocarboxylate was verified in the solid state. A five-coordinate tin(IV) was demonstrated in the solid state. In solution, a tetrahedral/trigonal bipyramidal configuration around Sn(IV) and a square planar geometry of Pd(II) was indicated by multinuclear NMR (1H and 13C) and UV-visible studies. The Pd(II) derivatives showed interaction with salmon sperm-DNA and caused an inhibition of alkaline phosphatase (ALPs). The antibacterial/antifungal potential of the coordination products varied with the nature of incorporated metal and a substitution pattern at tin(IV); the palladium metallation decreased the antimicrobial activities. The triorganotin(IV) products exhibited more powerful action against bacteria/fungi as compared to their diorganotin(IV) counterparts. The complexes displayed sufficiently lower hemolytic effects in vitro as compared to triton X-100 and slightly higher than PBS.

Density functional theory (DFT) study of polypyrrole-TiO2composites has been carried out to explore their optical, electronic and charge transfer properties for the development of an efficient photocatalyst. Titanium dioxide (Ti16O32) was interacted with a range of pyrrole (Py) oligomers to predict the optimum composition of nPy-TiO2composite with suitable band structure for efficient photocatalytic properties. The study has revealed that Py-Ti16O32composites have narrow band gap and better visible light absorption capability compared to individual constituents. The simulated results of band structure (band gap, and band edge positions), molecular orbitals, and UV–vis spectra of the optimized nPy-Ti16O32systems strongly support the existence of strong interactions between Py and TiO2in the composite. A red-shifting in λmax, narrowing band gap, and strong intermolecular interaction energy (-41 to −72 kcal/mol) of nPy-Ti16O32composites confirm the existence of strong covalent type interactions. Electron−hole transferring phenomena are simulated with natural bonding orbital analysis where Py oligomers found as donor and Ti16O32as an acceptor in nPy-Ti16O32composites.

Building-Integrated Concentrated Photovoltaic (BICPV) systems integrate easily into built environments, replacing building material, providing benefits of generating electricity at the point of use, allowing light efficacy within the building envelope and providing thermal management. This paper presents a novel experimental evaluation of phase change materials (PCM) to enhance performance of low concentration BICPV system via thermal regulation. Previous studies have primarily focussed on temporal and spatial studies of PCM temperature within the BIPV systems but the current work also discusses the effect of PCM on electrical parameters of the BICPV systems. Due to the inadequacy of the earlier reported model, a new analytical model is proposed and implemented with the in-house controlled experiments. Paraffin wax based RT42 was used within an in-house designed and fabricated PCM containment. An indoor experiment was performed using highly collimated continuous light source at 1000 Wm-2. Results show an increase in relative electrical efficiency by 7.7% with PCM incorporation. An average reduction in module centre temperature by 3.8°C was recorded in the BICPV–PCM integrated system as compared to the naturally ventilated system without PCM. Studies showed that PCM effectiveness varies with irradiance; an increase in relative electrical efficiency by 1.15% at 500 Wm-2, 4.20% at 750 Wm-2 and 6.80% at 1200 Wm-2 was observed.

Aim to determine the relationship between the chest radiographic patterns of PTB and CD4+ cell count among HIV-infected patients at FMC Katsina, Nigeria. Background the diagnostic usefulness plain chest X-ray (CXR) for patients with HIV/PTB co-infection is dependent on the degree of immunosuppression. Materials and methods We obtained and analysed, retrospectively, the hospital records of 182 patients treated for PTB with or without HIV infection at FMC Katsina, between 1st of January to 31st December, 2010. The Chest radiographic (CXR) features of PTB were reported as typical or atypical. Ziehl–Neelsen stained smear results were also used. Results of the 182 patients’ records used for this study, 102 (56.0%) males and 80 (44.0%) females with mean age of 40.2 ± 15.6 years and range of 18–85 years. The CXR of 182 patients recorded showed that 140 (76.9%) have typical features of PTB with 42 (23.1%) reported as atypical features. Those with HIV/PTB co-infection showed significantly higher atypical CXR features (p = 0.000) and even based on their CD4 cell count (p = 0.017). Conclusion Atypical chest radiographic features are commoner among HIV-infected PTB patients, especially those with low CD4+ cell counts, who also have low sputum smear yield. Providing facilities for TB culture in health care centres in Nigeria may reduce misdiagnosis.

Graphene (GR) and its derivatives are promising materials on the horizon of nanotechnology and material science and have attracted a tremendous amount of research interest in recent years. The unique atom-thick 2D structure with sp2 hybridization and large specific surface area, high thermal conductivity, superior electron mobility and chemical stability has made GR and its derivatives extremely attractive components for composite materials for solar energy conversion, energy storage, environment purification and biosensor applications. This review gives a brief introduction of GR's unique structure, band structure engineering, physical and chemical properties, recent energy-related progress of GR-based materials in the field of energy conversion (e.g. photocatalytic, photoelectrochemical water splitting, CO2 reduction, dye sensitized and organic solar cells, and photosensitizer in photovoltaic devices) and energy storage (batteries, fuel cell and supercapacitors) applications. The vast coverage of advancements in environmental applications of GR-based materials for photocatalytic degradation of organic pollutants, gas sensing and removal of heavy metal ions is presented. Additionally, the presences of graphene composites in the bio-sensing field have been discussed in this review. We concluded the review with remarks on the challenges, prospective and further development of GR-based materials in the exciting field of energy, environment, and bioscience.

Abstract Quantum mechanical calculations are performed to establish the structure of an oligomer of aniline and pyrrole [Poly(Ani-co-Py)], through comparison of experimental and theoretically calculated properties, including conductivity. The copolymer was synthesized through chemical oxidative polymerization and then confirmed from the experimental IR, UV-vis, mass spectra, elemental, XRD, TGA, and SEM analysis. Quantum mechanical calculations are performed at Density Functional Theory (DFT) and Time dependent DFT (TD-DFT) methods for the electronic and spectroscopic properties of the oligomer. A very nice correlation is found between the theory and experiment which consequences the structure of Poly(Ani-co-Py). Poly(Ani-co-Py) is not explored like other conducting polymers; however, by tuning this molecular structure, the electro-active nature of this material can be enhanced adequately.

A series of four new porphyrin-furan dyads were designed and synthesized by having anchoring group either at meso-phenyl or pyrrole-β position of a zinc porphyrin based on donor-π-acceptor (D-π-A) approach. The porphyrin macrocycle acts as donor, furan hertero cycle acts as π-spacer and either cyanoacetic acid or malonic acid group acts as acceptor. These dyads were fully characterized by UV-Visible, 1H NMR, MALDI-MS and fluorescence spectroscopies and cyclic voltammetry. Both of the observed and TD-DFT simulated UV-vis spectra has strong correllation which validate and confirm the synthesiszed dyads and theoretical method for this type of compounds. Both soret and Q-bands are red shifted in the case of pyrrole-β substituted dyads. The redox potentials of all four dyads are not altered in comparison with their individual constituents. The dyads were tested in dye sensitized solar cells and found pyrrole-β substituted zinc porphyrins are showing better performance in comparison with the corresponding meso-phenyl dyads. Optical band gap, Natural bonding, and Molecular bonding orbital (HOMO-LUMO) analysis are in favour of pyrrole-β substituted zinc porphyrins contrast to meso-phenyl dyads.

Comprehensive theoretical and experimental studies of a natural product, 8-hydroxyisodiospyrin (HDO) have been carried out. Based on the correlation of experimental and theoretical data, an appropriate computational model was developed for obtaining the electronic, spectroscopic, and thermodynamic parameters of HDO. First of all, the exact structure of HDO is confirmed from the nice correlation of theory and experiment, prior to determination of its electroactive nature. Hybrid density functional theory (DFT) is employed for all theoretical simulations. The experimental and predicted IR and UV-vis spectra [B3LYP/6-31+G(d,p) level of theory] have excellent correlation. Inter-molecular non-covalent interaction of HDO with different gases such as NH3, CO2, CO, H2O is investigated through geometrical counterpoise (gCP) i.e. B3LYP-gCP-D3/6-31G∗ method. Furthermore, the inter-molecular interaction is also supported by geometrical parameters, electronic properties, thermodynamic parameters and charge analysis. All these characterizations have corroborated each other and confirmed the electroactive nature (non-covalent interaction ability) of HDO for the studied gases. Electronic properties such as Ionization Potential (IP), Electron Affinities (EA), electrostatic potential (ESP), density of states (DOS), HOMO, LUMO, and band gap of HDO have been estimated for the first time theoretically.

Sensitivity and selectivity of polypyrrole (PPy) toward NH3, CO2, and CO have been studied at density functional theory (DFT). PPy oligomers are used both in the doped (PPy+) and neutral (PPy) form for their sensing abilities to realize the best state for gas sensing. DFT calculations are performed at the hybrid functional, B3LYP/6-31G(d), level of theory. Detection/interaction of CO is investigated from carbon [CO(1)] and oxygen termini of CO [CO(2)]. Interaction energies and charge transfer are simulated which reveal the sensing ability of PPy toward these gases. Furthermore, these results are supported by frontier molecular orbital energies and band gap calculations. PPy, in both the doped and neutral state, is more sensitive to NH3 compared to CO2 and CO. More interestingly, NH3 causes doping of PPy and dedoping of PPy+, providing evidence that PPy/PPy+ is an excellent sensor for NH3 gas. UV-vis and UV-vis-near-IR spectra of nPy, nPy+, and nPy/nPy+-X complexes demonstrate strong interaction of PPy/PPy+ with these atmospheric gases. The better response of PPy/PPy+ toward NH3 is also consistent with the experimental observations.

Density functional theory (DFT) and phytochemical study of a natural product, Diospyrin (DO) have been carried out. A suitable level of theory was developed, based on correlating the experimental and theoretical data. Hybrid DFT method at B3LYP/6-31G (d,p) level of theory is employed for obtaining the electronic, spectroscopic, inter-molecular interaction and thermodynamic properties of DO. The exact structure of DO is confirmed from the nice validation of the theory and experiment. Non-covalent interactions of DO with different atmospheric gases such as NH3, CO2, CO, and H2O were studied to find out its electroactive nature. The experimental and predicted geometrical parameters, IR and UV-vis spectra (B3LYP/6-31+G (d,p) level of theory) show excellent correlation. Inter-molecular non-bonding interaction of DO with atmospheric gases is investigated through geometrical parameters, electronic properties, charge analysis, and thermodynamic parameters. Electronic properties include, ionization potential (I.P.), electron affinities (E.A.), electrostatic potential (ESP), density of states (DOS), HOMO, LUMO, and band gap. All these characterizations have corroborated each other and confirmed the presence of non-covalent nature in DO with the mentioned gases.

Nanostructured nickel oxide (NiO) photoelectrodes were fabricated with controlled morphology and texture using single-step aerosol-assisted chemical vapour deposition (AACVD). The durable one-step film fabrication process resulted in highly crystalline columnar structure. Texture controlled films were also fabricated from granular to crystalline columnar morphology by controlling the deposition temperature. The thin film electrodes are highly reproducible and possess an optical bandgap of ~3.7 eV and exhibit cathodic photocurrent.

Nanostructured α-Fe2O3 thin film electrodes were deposited by aerosol-assisted chemical vapour deposition (AACVD) for photoelectrochemical (PEC) water splitting on conducting glass substrates using 0.1 M methanolic solution of Fe(acac)3. The XRD analysis confirmed that the films are highly crystalline α-Fe2O3 and free from other iron oxide phases. The highly reproducible electrodes have an optical bandgap of ~2.15 eV and exhibit anodic photocurrent. The current-voltage characterization of the electrodes reveals that the photocurrent density strongly depended on the film morphology and deposition temperature. Scanning electron microscopy (SEM) analysis showed a change in the surface morphology with the change in deposition temperature. The films deposited at 450 °C have nanoporous structures which provide a maximum electrode/electrolyte interface. The maximum photocurrent density of 455 μA/cm2 was achieved at 0.25 V vs. Ag/AgCl/3M KCl (~1.23 V vs. RHE) and the incident photon to electron conversion efficiency (IPCE) was 23.6% at 350 nm for the electrode deposited at 450 °C.

A simple method of depositing morphology- and phase-tailored thin films of copper(i) oxide and metallic copper from [Cu(dmae)(TFA)]4·CH2Cl2 (1), where dmae is N,N-dimethylaminoethanolato and TFA is trifluoroacetato, on glass substrates by aerosol-assisted chemical vapour deposition is demonstrated. The tetrameric precursor 1 was synthesized and its structure was determined by single-crystal X-ray crystallography. Precursor 1 was applied for the deposition of nanostructured thin films of copper(i) oxide and copper nanowires at 250 and 375°C respectively. The deposited thin films were characterized by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray diffraction, and ultraviolet-visible spectroscopy. The results indicate that the phase and morphology of the deposited material are strongly dependent on deposition temperature. UV-vis studies reveal that copper(i) oxide films with a band gap of 2.48eV may find possible applications in tandem photoelectrochemical devices as light-absorbing material. © CSIRO 2014.

Studies were conducted to investigate the influence of deposition solution composition (methanol ≤ the deposition solvent ≤ ethanol) on their physical and chemical properties that matters in the aerosol formation and subsequent decomposition during the aerosol assisted chemical vapour deposition (AACVD) of ZnFe2O4 electrodes. The FEGSEM studies found that the change of composition of deposition solution produced a dramatic change in the ZnFe2O4 electrode texture. The ZnFe 2O4 electrodes deposited from methanol as well as predominately methanolic solvents had a relatively compact morphology. In contrast, the electrodes deposited from ethanol as well as predominately ethanolic solvents showed highly textured rod-like structure at nanoscale. The change in electrode texture is explained in terms of changes occurred in precursor decomposition pathways from heterogeneous and homogeneous when the composition of deposition solution is systematically varied. The photoelectrochemical (PEC) properties of all ZnFe2O4 electrodes were studied by recording J-V characteristics under AM1.5 illumination and the photocurrent spectra. The textured electrodes exhibited a significantly higher photocurrent compared to their compact counterparts. This is attributed to the improved photogenerated minority carrier collection at the ZnFe2O4/electrolyte interface as the average feature size gradually decreased. The photocurrent density (at 0.25 V vs. Ag/AgCl/3M KCl) increases rapidly when the electrode is deposited from the solvent containing 60% ethanol and above, which is in close agreement with the textural changes taken place in ZnFe2O4 electrodes. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Acanthite (Ag2S) thin films were fabricated on fluorine doped tin oxide coated conducting glass substrates by aerosol assisted chemical vapor deposition (AACVD) using silver cluster [Ag4{S2CN(C 2H5)2}3(C5H 5N)2]n·nNO3·2nH 2O (1) [where (S2CN(C2H5) 2) = diethyldithiocarbamate, C5H5N = pyridine] as a single source precursor. Cluster (1) was synthesized by the reaction of sodium diethyldithiocarbamate with silver nitrate in a mixture of acetone and pyridine. (1) was analyzed by melting point, elemental analysis, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, thermogravimetry and single crystal X-ray studies. Single crystal X-ray studies showed that (1) crystallizes in the triclinic crystal system with a = 11.4372(3), b = 11.6768(3), and c = 16.3672(4) Å and α = 105.817(3), β = 97.891(3), and γ = 93.274(3) in the space group P-1. Thermogravimetric analysis revealed that (1) undergoes facile thermal decomposition at 400 C to give a stable residual mass consistent with the formation of Ag2S. Thin films grown from a 0.02 M solution of (1) in pyridine at 350 and 400 C using AACVD technique were characterized by powder X-ray diffraction, field emission scanning electron microscopy (FESEM), energy dispersive X-ray and ultraviolet-visible spectrophotometry. FESEM images of the films exhibited well-defined nanorods with length > 1000 nm and diameter 100-150 nm grown without any cracks, fractures or directional preference. A band gap of 1.05 eV was estimated by extrapolating the linear part of a Tauc plot recorded for the films. The photoelectrochemical (PEC) characteristics recorded under Air Mass 1.5 illumination indicated a photocurrent density of 220 μA cm- 2 at 0.0 V vs Ag/AgCl/3 M KCl. The optical and PEC characteristics of the deposited thin films proved their suitability for PEC applications. © 2013 Elsevier B.V. All Rights Reserved.

A single molecular heterobimetallic complex, [Co 2Ti(μ 3-O)(TFA) 6(THF) 3] (1) [TFA = trifluoroacetate, THF = tetrahydrofuran], was synthesized, structurally and spectroscopically characterized and implemented as a single-source precursor for the preparation of CoTiO 3-CoO composite thin films by aerosol-assisted chemical vapour deposition (AACVD). The precursor complex was prepared by interaction of Co(OAc) 2.4H 2O [OAc = (CH 3COO -)] with Ti(iso-propoxide) 4 in the presence of trifluoroacetic acid in THF, and was analysed by melting point, CHN, FT-IR, single-crystal X-ray diffraction and thermogravimetric analysis. The precursor complex thermally decomposed at 480°C to give a residual mass corresponding to a CoTiO 3-CoO composite material. Good-quality crystalline CoTiO 3-CoO composite thin films deposited at 500°C by AACVD and characterized through powder X-ray diffraction and scanning electron microscopy/energy-dispersive X-ray spectroscopy show that the crystallites have a rose-flower-like morphology with an average petal size in the range of 2-6 μm. © 2012 John Wiley & Sons, Ltd.

TiO 2 electrodes are deposited on FTO-glass substrates at 350 and 400 °C by aerosol-assisted chemical vapour deposition (AACVD) and the deposited TiO 2 electrodes are irradiated with microwave radiation (2.45 GHz) at various percentages (10, 25, 50, and 100%). X-ray diffraction (XRD) pattern shows that the deposited electrodes have anatase phase TiO 2 oriented in the (101) direction, and the crystallinity of these electrodes increases after microwave treatment. Field emission gun scanning electron microscopy (FEG-SEM) surface topography analysis proves the preservation of the nanostructure after exposure to various percentages of microwave radiation. The photoelectrochemical (PEC) studies prove a threefold enhancement of photocurrent density of AACVD-produced TiO 2 electrodes after 100% microwave irradiation. This improved performance of PEC properties is attributed to improvements in the crystallinity and the particle-necking properties. The results presented demonstrate that microwave processing is a promising alternative method to conventional sintering for TiO 2 photoanodes. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inhibition effects of novel organotin(IV) esters of (E)-4-oxo-4-((3-trifluoromethyl)phenyl)amino)but-2-enoic acid have been studied against bacterial, fungal, tumoral and insecticidal strains. The complexes have shown potency against all these strains and is attributed to the multiple interactive sites of the ligand that not only change the environment around tin but also can make interactions with DNA. The synthesized complexes were characterized by physical, spectral, analytical and multinuclear nmr ( 1H, 13C, 119Sn) data. The X-ray structure analysis of the complex is reported. © 2012 Springer Science+Business Media, LLC.

Heterobimetallic molecular Cu-Ni and Cu-Co complexes [Cu2Ni 4(acac)2(dmae)2(dmaeH)2(OH)(TFA) 6] (1) and [Cu2Co4(acac)2(dmae) 2(dmaeH)2(OH)(TFA)6] (2) [dmae = N,N-dimethylaminoethanol, TFA = trifluoroacetic acid and acac = 2,4-pentanedionate] were prepared and tested as precursors for the deposition of mixed metal oxide composite thin films. The complexes were synthesized by reaction of the tetrameric copper(ii) complex [Cu(dmae)(TFA)]4 with M(acac)2·xH2O [M = Ni, x = 2; Co, x = 1] in THF and were characterized by melting point, elemental analysis, FT-IR spectroscopy, TG/DTG and single-crystal X-ray diffraction. The complexes are isomorphous and crystallize in the triclinic centrosymmetric space group P1. Aerosol assisted chemical vapour deposition (AACVD) studies carried out on (1) and (2) showed that they are promising precursors for the deposition of thin films of crystalline CuO-NiO and Cu2O-CoO composites, respectively. The size, shape, surface morphology, microstructure, chemical composition and crystallinity of the resulting mixed-metal oxide composite thin films were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis proved that the thin films are crystalline, uniform, smooth and tightly adherent to the substrates. © the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.

Rate constants for recombination and hole transfer during oxygen evolution at illuminated α-Fe(2)O(3) electrodes were measured by intensity-modulated photocurrent spectroscopy and found to be remarkably low. Treatment of the electrode with a Co(II) solution suppressed surface recombination but did not catalyse hole transfer. Intermediates in the reaction were detected spectroscopically.

The kinetics of light-driven oxygen evolution at polycrystalline alpha-Fe2O3 layers prepared by aerosol-assisted chemical vapour deposition has been studied using intensity modulated photocurrent spectroscopy (IMPS). Analysis of the frequency-dependent IMPS response gives information about the competition between the 4-electron oxidation of water by photogenerated holes and losses due to electron-hole recombination via surface states. The very slow kinetics of oxygen evolution indicates the presence of a kinetic bottleneck in the overall process. Surface treatment of the alpha-Fe2O3 with dilute cobalt nitrate solution leads to a remarkable improvement in the photocurrent response, but contrary to expectation, the results of this study show that this is not due to catalysis of hole transfer but is instead the consequence of almost complete suppression of surface recombination.

New hexanuclear zinc complex, Zn6(OAc)8(μ-O) 2(dmae)4 (1) (OAc = acetato, dmae = N,N-dimethyl aminoethanolato) has been synthesized and characterized by its melting point, elemental analysis, Fourier transform infrared spectroscopy, atmospheric-pressure chemical-ionization mass spectrometry, thermal gravimetric analysis, and single crystal X-ray analysis. The complex (1) crystallizes in the monoclinic space group C2/c. The high solubility of complex (1) in organic solvents such as alcohol, THF, and toluene and low decomposition temperature as compared to Zn(OAc)2 make it a promising single source candidate for the deposition of nanostructured ZnO thin films by aerosol-assisted chemical vapor deposition. Films with various nanostructures, morphology, and crystallographic orientation have been deposited by controlling the deposition temperature. The deposited films have been characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis. The optical characterization of ZnO films deposited on the FTO substrate show a direct band gap of 3.31 eV, and the photoelectrochemical study revealed that the photocurrent onset is at about -0.32 V, whereas no photocurrent saturation was observed. The I-V measurements designated the deposited films as ohmic semiconductors. © 2012 American Chemical Society.

Thin mesoporous films of α-Fe(2)O(3) have been prepared on conducting glass substrates using layer-by-layer self-assembly of ca. 4 nm hydrous oxide nanoparticles followed by calcining. The electrodes were used to study the oxygen evolution reaction (OER) in the dark and under illumination using in situ potential-modulated absorption spectroscopy (PMAS) and light-modulated absorption spectroscopy (LMAS) combined with impedance spectroscopy. Formation of surface-bound higher-valent iron species (or "surface trapped holes") was deduced from the PMAS spectra measured in the OER onset region. Similar LMAS spectra were obtained at more negative potentials in the onset region of photoelectrochemical OER, indicating involvement of the same intermediates. The impedance response of the mesoporous α-Fe(2)O(3) electrodes exhibits characteristic transmission line behavior that is attributed to slow hopping of holes, probably between surface iron species. Frequency-resolved PMAS and LMAS measurements revealed slow relaxation behavior that can be related to the impedance response and that indicates that the lifetime of the intermediates (or trapped holes) involved in the OER is remarkably long.

[Ag(2)(9-aca)(2)] (1) (9-acaH = 9-anthracenecarboxylic acid) reacts with a series of imidazoles to give [Ag(imidH)(2.3)(CH(3)CN)(0.7)](9-aca) (3), [Ag(6)(imidH)(4)(9-aca)(6)(MeOH)(2)] (4), {[Ag(1-Me-imid)(2)](2)[Ag(4)(9-aca)(6)]} (5), {[Ag(1-Bu-imid)(2)](2)[Ag(4)(9-aca)(6)]} (6) and [Ag(apim)](9-aca)·H(2)O (7) (imidH = imidazole; 1-Me-imid = 1-methylimidazole; 1-Bu-imid = 1-butylimidazole; apim = 1-(3-aminopropyl)imidazole). The mononuclear complex 3, hexanuclear 4-6, and polymeric 7, were all characterised using X-ray crystallography. While many of the complexes possess excellent in vitro antifungal and antibacterial activities they are, unanimously, more effective against fungal cells. The insect, Galleria mellonella, can survive high doses of the Ag(i) complexes administered in vivo, and a number of the complexes offer significant protection to larvae infected with a lethal dose of pathogenic Candida albicans cells.

A heterobimetallic single molecular precursor, [Fe2Ti 4(μ-O)6(TFA)8(THF)6] (1) [TFA = trifluoroacetate, THF = tetrahydrofuran], was synthesized by the simple reaction of [Fe3O(OAc)6(H2O)3]NO 3·4H2O [OAc = acetato] with tetrakis(2- ethoxyethanalato)titanium(IV) in the presence of trifluoroacetic acid in THF. The synthesized precursor was analyzed by melting point, CHN analysis, FTIR, single crystal X-ray diffraction and thermogravimetric analysis. Complex (1) crystallizes in the orthorhombic space group Pca21 with cell dimensions a = 19.2114(14), b = 20.4804(15) and c = 17.2504(12) , and the complex undergoes thermal decomposition at 490 °C to give a residual mass corresponding to an Fe2TiO5-TiO2 composite mixture. The synthesized precursor was utilized for deposition of Fe 2TiO5-TiO2 composite thin films by aerosol-assisted chemical vapor deposition (AACVD) on glass substrates at 500 °C using argon as the carrier gas. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray powder diffraction (XRD) analyses of the thin films suggest the formation of good quality crystalline thin films of an Fe2TiO5-TiO2 composite with an average grain size of 0.105-0.120 μm. © 2011 Elsevier B.V. All rights reserved.

The effect of ZnO thin films as seed layers deposited by Aerosol Assisted Chemical Vapour Deposition (AACVD) and electrodeposition were systematically investigated on the growth and alignment behaviour of ZnO nanorods. A series of compact and uniform ZnO seed layers with different deposition times (1, 2 and 3 mins) were deposited on FTO (Fluorine-doped tin oxide) substrate using AACVD technique. For comparison, another series of ZnO seed layers were also deposited on FTO substrate by electrodeposition. The ZnO nanorods were grown on the seed layer coated FTO substrates by the chemical bath deposition (CBD). The XRD and SEM results show that vertically aligned ZnO nanorods are formed on seed layer deposited by AACVD as compared to the seed layer deposited by electrodeposition. Copyright © 2011 American Scientific Publishers. All rights reserved.

The mixed metal complex [Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)Br]·THF (1) and its isostructural analogues ([Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)Cl]·THF (2) and [Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)Cl/Br]·THF (3)) have been prepared by a simple metal ligand assembly method and were characterized by their melting points, elemental analysis, IR spectroscopy, thermogravimetry and single crystal X-ray structures. The compounds are distinguished only by the nature of the halide ions and are made up of the same [Zn(TFA)(3)(μ-OH)Cu(3)(dmae)(3)X]·THF molecular building block with Cu(3)ZnO(4) cubane moieties as the central core in which the four metal ions and four oxygen atoms are joined together in alternate positions of the cuboid. All the complexes crystallize with similar packing and crystallographically related symmetry settings, distinguished mainly by the degree of disorder within the complexes and the ordering of the complexes in the structures. The triclinic cell of (1) emulates the monoclinic cell of (2) and is pseudomerohedrally twinned by a symmetry operation of the monoclinic cell. The molecules in (2) are 1:1 disordered around a crystallographic mirror plane. The structure of the mixed halogen compound (3) in turn is a superstructure of the less symmetric structures of (1) and (2) formed by ordering of the complexes along the longest axis of (3). Aerosol-assisted chemical vapour deposition (AACVD) experiments showed that they are promising precursors to deposit thin films of crystalline Cu/ZnO composites. The surface morphology, microstructure, chemical composition and crystallinity of the resulting Cu/ZnO composite thin films were analysed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX), which suggest that the films are thin, crystalline, uniform, smooth and tightly adherent to the substrates with average crystallite sizes in a range between 40.2 and 80.0 nm. Particle sizes, shapes and film morphology were investigated as a function of precursor and decomposition temperature.

The demand for nanostructured metal oxide electrodes in optoelectronic devices requires investigation of simple and scalable deposition processes. In this study we demonstrate the flexibility of aerosol-assisted chemical vapor deposition to fabricate single and mixed oxide electrodes. The composition, structure, and morphology can easily be controlled by varying the Zn:Sn ratio of the precursor solution. X-ray diffractometric analysis proved that the structure and composition were strongly dependent on the Zn concentration in the precursor. ZnO, SnO2, and a range of ZnO/SnO2 composite electrodes were fabricated by gradually decreasing the Zn content in the precursor solution. A diverse range of nanostructures were also created as the Zn:Sn ratio was varied. The morphology of the electrodes changed from nanoparticles, to nanoplates and nanocolumns with the change in the Zn:Sn ratio. Diffuse reflectance spectroscopy confirmed the high optical absorption of the materials in the UV region. It was found that by controlling the Zn:Sn ratio of the precursor, the optical properties of the electrodes could be finely tuned between the bandgap (Eg) of ZnO (Eg∼3.31 eV) and SnO2 (Eg∼3.55 eV). © 2011 the American Ceramic Society.

This article describes the synthesis of triorganotin(IV)-, chlorodiorganotin(IV)- and diorganotin(IV) 4-ethoxycarbonylpiperazine-1-carbodithioates with general R3SnL {where R = CH3 (1), n-C4H9 (2) and C6H5 (3)}, R2SnClL {where R = CH3 (4), n-C4H9 (5) and C6H5 (6)} and R2SnL2 {where R = CH3 (7), n-C4H9 (8) and C6H5 (9)}, respectively. The coordination behavior of ligand (L) in all compounds was investigated by different analytical techniques such as FT-IR and multinuclear NMR. X-ray single crystal analysis confirmed supramolecular structure for compounds (3) and (4) with distorted trigonal-bipyramidal and distorted square-pyramidal geometries, respectively. The compounds have pronounced antimicrobial (antibacterial and antifungal) potency and moderate insecticidal activity. These compounds also inhibit effectively the activity of urease enzyme. © 2010 Elsevier B.V. All rights reserved.

Bi2S3 nanotubes and nanoparticle in the form of thin films were deposited on fluorine doped SnO2 (FTO) coated conducting glass substrates by Aerosol Assisted Chemical Vapor Deposition (AACVD) using tris-(N,N-diethyldithiocarbamato)bismuth(III), [Bi(S2CN(C 2H5)2)3]2 (1) as a precursor. Thin films were deposited from solutions of (1) in either chloroform, dichloromethane, or a 1:1 mixture of chloroform and toluene at temperature between 350 to 450 °C and characterized by X-ray diffraction (XRD), UV-vis spectroscopy, field emission gun scanning electron microscopy (FEGSEM), and energy dispersive X-ray (EDX) analysis. FEGSEM images of films deposited from chloroform or dichloromethane exhibit well-defined and evenly distributed nanotubes with an average internal diameter of 40 nm. Films deposited from chloroform/toluene, on the other hand, have compact nanostuctured morphology. Bandgaps of 1.85 and 1.8 eV were estimated for nanotubes and nanoparticles, respectively, by extrapolating the linear part of the Tauc plot recorded for the films. The n-type Bi2S3 thin films display a reasonable photoactivity under illumination and are thus promising candidates for photoelectrochemical applications. The photoelectrochemical characteristics recorded under AM 1.5 illumination indicated photocurrent density of 1.9 mA/cm2 and 1.0 mA/cm2 at 0.23 V versus Ag/AgCl/3 M KCl for the films deposited from chloroform and chloroform/toluene, respectively. The photocurrent is among the highest reported for any Bi2S3 photoelectrode to date. Repeated illumination cycles show that the Bi 2S3 thin films display a reasonable photosensitivity and response indicating their potential to be used in photodetector and optoelectronic nanodevice applications. © 2010 American Chemical Society.

Semiconducting nanocrystalline ZnFe 2O 4 thin films were deposited by aerosol-assisted chemical vapour deposition (AACVD) for photoelectrochemical (PEC) water splitting. The effect of deposition parameters such as solvent type, temperature and deposition time on PEC properties has been investigated. The SEM analysis illustrated that the morphology of the films changes significantly with the change of solvent. The films deposited from ethanolic precursor solution have a morphology consisting of interconnected cactus-like ZnFe 2O 4 structure growing vertically from the FTO substrate. The current-voltage characterization proved that the nanocrystalline ZnFe 2O 4 electrodes exhibit n-type semiconducting behaviour and the photocurrent was found strongly dependent on the deposition solvent, deposition temperature and deposition time. The maximum photocurrent density of 350 μA/cm 2 at 0.23 V vs. Ag/AgCl/3 M KCl (∼1.23 V vs. RHE) was obtained for the ZnFe 2O 4 electrode synthesized using the optimum deposition temperature of 450 °C, the deposition time of 35 min, and 0.1 M solution of (1) in ethanol. The electrode gave an incident photon to electron conversion efficiency of 13.5% at an applied potential of 0.23 V vs. Ag/AgCl/3 M KCl at 350 nm. The donor density of the ZnFe 2O 4 was 3.24 × 10 24 m -3 and the flatband potential is approximately -0.17 V, which remarkably agrees with the photocurrent onset potential of -0.18 V vs. Ag/AgCl/3 M KCl. © 2010 Elsevier B.V. All rights reserved.

Objective: the purpose of this study was to determine the normal range of spleen size in an adult African population, and compare the findings to published data to determine any correlation with ethnicity. Materials and methods: Three hundred and seventy-four African adults without conditions that can affect the spleen or splenic abnormalities were evaluated with ultrasonography. Spleen length, width and thickness were measured and spleen volume calculated. Spleen size was correlated with age, gender, height, weight, and body mass index. Results: the mean spleen volume was 120 cm3. Spleen volume correlated with spleen width (r = 0.85), thickness (r = 0.83) and length (r = 0.80). Men had a larger mean spleen volume than women. No correlation was found between spleen volume and age, weight, height, or body mass index. Conclusion: Mean spleen volume in African adults is smaller than data from Western sources, and cannot be explained by difference in body habitus. Crown Copyright © 2009.

A single source heterobimetallic complex [Fe2(acac)4(dmaeH)2][ZnCl4] (1) (acac = 2,4-pentanedionate, dmaeH = N,N-dimethylaminoethanol), was synthesized in high yield. The complex was analyzed by melting point, Fourier transfer infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The structure of the cation was established by single crystal X-ray analysis on a derivative, [Fe2(acac)4(dmaeH)2][ZnCl3(THF)]2·THF (1a) (THF = tetrahydrofuran). TGA analysis showed that complex (1) undergoes facile thermal decomposition at 450 °C to give ZnFe2O4 residue. In-house designed aerosol assisted chemical vapour deposition equipment was used to deposit thin films of ZnFe2O4 on fluorine doped SnO2 coated conducting glass substrate at 450 °C. X-ray diffraction analysis proved the formation of crystalline ZnFe2O4 phase and scanning electron microscopy revealed the film morphology with well defined crystalline particles evenly distributed in the range 150-200 nm. The indirect and direct bandgap energies of the thin films were estimated to be 1.76 and 2.10 eV, respectively. © 2009 Elsevier B.V. All rights reserved.

ZnO-SnO2 composite electrodes have been deposited on fluorine-doped tin oxide (FTO) substrates by aerosol assisted chemical vapour deposition (AACVD) from a single source precursor solution. The electrodes were characterised using X-ray diffraction (XRD), atomic force microscopy (AFM), field emission gun scanning electron microscopy (FEGSEM) and energy dispersive X-ray analysis (EDX). The composite electrodes were used to construct ETA solar cells with the following structure; FTO/ZnO-SnO2/In2S 3/PbS/PEDOT:PSS/Cgraphite/FTO. Performance of the cells were characterised by measuring the current-voltage (I-V) and incident photon to electron conversion efficiencies (IPCE). The effect of Zn:Sn ratio in the precursor and effect of post deposition annealing temperature on the morphology of the composite layers, in relation to the performance of the fabricated cells were investigated. The highest performing cells were fabricated using the composite anode deposited from 50:50 mol% Zn:Sn in the precursor with post deposition annealing at 400 °C. I-V characterisation under AM 1.5 solar simulated light reveals that the cell had an open circuit voltage (V oc) ∼ 0.32 V, short circuit current density (Jsc) ∼ 8.2 mA cm-2, a fill factor (FF) ∼ 0.26, an overall efficiency (η) ∼ 0.68% and a maximum IPCE ∼ 30%. The experimental IPCE agrees well with theoretically estimated IPCE when the PbS surface coverage is about 0.1-0.2. © 2010 Elsevier B.V. All rights reserved.

Homobi-, -tri- and -tetranuclear copper(II) oligomeric complexes, [Cu(dmap)(OAc)(H2O)]2-H2O (1), [Cu 3(dmae)3(acac)2- Cl] (2) and [Cu(dmae)(TFA)]4 (3), have been prepared by reacting Cu(OAc) 2-H2O with dmapH, [Cu(dmae)Cl]4 with Na(acac) and Cu(dmae)2 with Cu(TFA)2 [dmae = (N,N-di- methylamino)ethanolate, dmap = (N,N-dimethylamin.o)propanolate, TFA = trifluoroacetate, and acac = 2,4-pentanedionate], respectively and characterized by melting point, elemental analysis, FT-IR and single-crystal X-ray diffraction. The crystal analysis shows that bi- (1) and trinuclear (2) complexes crystallize in the triclinic, while the tetranuclear complex 3 belongs to the monoclinic crystal system. TGA and AACVD experiments prove that the complexes undergo facile thermal decomposition in the temperature range 300-460 °C to deposit thin films of pure copper metal. The SEM and XRD analyses of the thin films suggest the formation of Cu crystallites with grain sizes of 100-340 nm (for 1), 75.4-90.8 nm (for 2 and 3). © Wiley-VCH Verlag GmbH & Co. KGaA.

Nanostructured thin films of α-Fe2O3 were prepared through atmospheric chemical vapour deposition (APCVD) using ferrocene and iron pentacarbonyl as precursors. Higher optical absorption was observed for hematite films prepared using ferrocene, which was attributed to the higher packing density. Photoelectrochemical (PEC) studies of the films prepared using ferrocene showed superior performance to that of iron pentacarbonyl. Photocurrent density of 540 μA/cm2 and 1.5 μA/cm2 at 1.23 VRHE was achieved for hematite films prepared using ferrocene and iron pentacarbonyl, respectively. Our findings suggest that ferrocene can be used as a promising alternative to iron pentacarbonyl to prepare hematite photoelectrodes using APCVD. © 2008 Elsevier B.V. All rights reserved.

Heterobimetallic molecular precursors [Ba(dmap)4Cu 4(OAc)6·THF] (1) and [Ba(dmap)4Cu 4(TFA)6·THF] (2) [dmap = N,N- dimethylaminopropanolate, OAc = acetate and TFA = trifluoroacetate] for the deposition of barium-copper composite oxide thin films, were prepared by the interaction of Ba(dmap)2 with Cu(OAc)2 for 1 and Cu(TFA)2 for 2, in THF. Both heterobimetallic complexes were characterized by melting point, elemental analysis, FT-IR spectroscopy, mass spectrometry and single crystal X-ray diffraction. X-Ray crystallography shows that complex 1 crystallizes in the orthorhombic space group P212 121 with the cell dimensions a = 11.2621(11), b = 18.2768(17) and c = 24.541(2), while complex 2 crystallizes in the monoclinic space group C2/c with a = 23.9288(14), b = 19.8564(12), c = 25.5925(15) and β = 112.4390(10)°. Thermal gravimetric analysis shows that both complexes 1 and 2 undergo controlled thermal decomposition at 450 °C and 400 °C, respectively, to give mixed metal oxide composite thin films. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray powder diffraction (XRD) analyses of the thin films suggest the formation of good quality crystalline thin films of BaCuO2-CuO composites from both 1 and 2, with average grain sizes of 105 to 175 nm and 110 to 205 nm, respectively. © the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009.

Si-doped nanostructured hematite (R-Fe2O3) has attracted significant attention as a low-cost, high-efficiency candidate material for photoelectrochemical water splitting. In this work, we investigated the effect of Si incorporation on the preparation and performance of R-Fe 2O3 films produced by atmospheric pressure chemical vapor deposition (APCVD). Structural, optical, electrical, and photoelectrochemical characterization of doped and undoped hematite films was performed using XRD, FIB/SEM, Raman spectroscopy, UV-vis absorption spectroscopy, J-V and electrochemical capacitance measurements. It was concluded from the XPS data that Si is incorporated in the hematite structure as Si4+. The results suggest that Si-free additives as well as the use of fluorinated transparent conducting oxide (FTO) substrates can influence the preferred orientation of hematite films. It was also found that the incorporation of silicon at very low levels led to the formation of disorder in the hematite structure. Moreover, it is shown that the optical bandgap of Si-doped film increased with the increase of TEOS flow rate. It contributed to the reduction in the size of the hematite nanoparticles and the size quantization effect. The observed donor densities for the doped samples seemed to be much higher than the true values, mainly because the total capacitance measured was higher than space charge layer capacitance, which resulted from the surface area enhancement in the doped films. Therefore, it is considered that donor densities of doped films were smaller than that of the undoped hematite films. © 2009 American Chemical Society.

α-Fe2O3 thin film photoelectrodes were fabricated by aerosol-assisted chemical vapor deposition (AACVD) using a new hexanuclear iron precursor [Fe6(PhCOO)10(acac) 2(O)2(OH)2]'3C7H8 (1) (where PhCOO = benzoate and acac = 2,4-pentanedionate). The precursor (1) designed for AACVD has a low decomposition temperature and sufficient solubility in organic solvents and was synthesized by simple chemical techniques in high yield. It was characterized by melting point, FT-IR, X-ray crystallography, and thermogravimetry (TGA). The TGA analysis proved that complex (1) undergoes facile thermal decomposition at 475 °C to give iron oxide residue. In-house designed AACVD equipment was used to deposit highly crystalline thin films of α-Fe2O3 on fluorinedoped SnO2 coated glass substrates at 475 °C in a single step. The material properties were characterized by XRD, XPS, and Raman spectroscopy, and the results confirmed that films were highly crystalline α-Fe2O3 and free from other phases of iron oxide. Further analysis of XRD data of the thin films proved the formation of crystalline hematite with an average diameter of 35 nm. X-ray photoelectron spectroscopy (XPS) confirmed that Fe is present only in the Fe3+ oxidation state. Scanning electron microscopy (SEM) showed that the needle-like particles having length in the range of 100 to 160 nm with a diameter of 30-50 nm are sintered together to form a compact structure of the 80-nm-thick Ot-Fe2O3 layer. Optical, electrical, and photoelectrochemical studies were conducted by UV-vis, electrochemical impedance spectroscopy, and steady-state current-voltage plots. The optical bandgap was estimated, and it is about 2.13 eV. The donor density of the α-Fe 2O3 was 2.914 x 1023 m-3, and the flatband potential is approximately -0.86 V vs VAg/Agcl. The photoelectrochemical characteristics recorded under AM 1.5 illumination indicated that the photocurrent density of 600 μA cm-2 at 1.23 V vs RHE, which is among the highest reported for an undoped α-Fe 2O3 photoelectrode to date.

A single-source heterobimetallic complex Ni2Ti2(OEt)2(mu-OEt)6(acac)4 (1) (acac=2,4-pentanedionate), having a low decomposition temperature and sufficient solubility in organic solvents, was synthesized by simple chemical techniques in high yield and analyzed by melting point, FTIR, single crystal X-ray analysis and thermal analysis. The TGA analysis proved that complex (1) underwent facile thermal decomposition at 500 degrees C to give NiTiO3 residue. In-house designed aerosol assisted chemical vapor deposition equipment was used to deposit high quality thin films of NiTiO3 on a SnO2 coated conducting glass substrate at 500 degrees C. An XRD analysis of the thin films proved the formation of crystalline NiTiO3 with average grain size 42 nm. Scanning electron microscopic studies (SEM) show that the thin films consist of flat, plate-like nanoparticles. The current-potential characteristics recorded under AM1.5 illumination indicate that NiTiO3 thin films are anodic and the photocurrent density at 1.23 V vs RHE (Reversible Hydrogen Electrode) is about 40 microA cm(-2).

Thin films of halide free Cu-Co mixed metal oxide have been prepared at 390 °C from the heterobimetallic complex Co4(THF)4(TFA)8(μ-OH)2Cu2(dmae)2 · 0.5C7H8 (1) [dmae = N,N-dimethylaminoethanol ((CH3)2NCH2CH2O-), TFA = triflouroacetate (CF3COO-), THF = tetrahydrofurane (C4H8O)] which was prepared by the reaction of [Cu(dmae)Cl]4 and Co(TFA)2 · 4H2O. The precursor was characterized for its melting point, elemental composition, FTIR and X-ray single crystal structure determination. Thin films grown on glass substrate by using AACVD out of complex 1 were characterized by XRD and SEM. TGA and AACVD experiments reveal it to be a suitable precursor for the deposition of halide free Cu-Co mixed-metal oxide thin films at relatively low temperatures. © 2008 Elsevier B.V. All rights reserved.

The high nuclearity zinc complex, Zn6(OAc)8(μ-OH)2(dmae)2(dmaeH)2 (1) (OAc = acetate and dmaeH = N,N′-dimethylaminoethanol), having a low decomposition temperature and sufficiently high solubility in non-polar solvents, was synthesized by a simple chemical technique in high yield and analyzed by melting point, elemental analysis, FTIR, NMR, single crystal X-ray crystallography and thermal analysis. Aerosol-assisted chemical vapor deposition technique was used to deposit a high-quality thin film with good adhesion to the glass substrate at relatively low temperature (320 °C). Scanning electron microscopy of the film shows clearly distinct crystallites of uniform shape with 2.4-2.9 μm size. Powder X-ray diffraction measurements have indicated the deposition of a crystalline phase of hexagonal ZnO with space group P63mc. © 2007 Elsevier B.V. All rights reserved.

Heterobimetallic molecular precursors [Ti(4)(dmae)(6)(mu-OH)(mu-O)(6)Cu(6)(benzoate)(9)] (1) and [Ti(4)(dmae)(6)(mu-OH)(mu-O)(6)Cu(6)(2-methylbenzoate)(9)] (2) were prepared by the interaction of Ti(dmae)(4) [dmae=N,N-dimethylaminoethanolate] with Cu(benzoate)(2).2H(2)O for (2) and Cu(2-methylbenzoate)(2).2H(2)O for (2), respectively, in dry toluene, for selective deposition of Cu/Ti oxide thin films for possible technological applications. Both the complexes were characterized by melting point, elemental analysis, FT-IR, thermal analysis and single crystal X-ray analysis. Complex (1) crystallizes in the triclinic space group P-1 and complex (2) in the rhombohedral space group R-3. The TGA analysis proves that complexes (1) and (2) undergo facile thermal decomposition at 550 degrees C to form copper titanium mixed metal oxides. The SEM/EDX and XRD analyses suggest the formation of carbonaceous impurity free good quality thin films of crystalline mixtures of beta-Cu(3)TiO(4) and TiO(2) for both (1) and (2), with average grain sizes of 0.29 and 0.74 microm, respectively. Formation of two different homogeneously dispersed oxide phases is also supported by electrical impedance measurements.

The Cu atom in the title complex, [Cu(C9H7O2)(C4H11NO)2], lies on an inversion centre in an octa-hedral geometry and is coordinated by two bidentate chelating 2-(dimethyl-amino)ethanol groups and two monodentate cinnamate groups which are mutually trans to each other. The non-coordinated O atoms of the cinnamate ligands form intra-molecular hydrogen bonds to the OH groups of the 2-(dimethyl-amino)ethanol ligands, generating six-membered rings. © 2007 International Union of Crystallography. All rights reserved.

The structure of the title complex, [Ni2(C5H 7O2)4(H2O)2]·0. 5H2O, is dimeric and corresponds to the trimeric structure of bis(acetylacetonato)nickel(II) in which one Ni(acac)2 unit is replaced by two water molecules. The centrosymmetric molecule comprises two O-O edge-shared octahedra. The asymmetric unit contains two half-molecules of the complex and one water molecule. © 2007 International Union of Crystallography. All rights reserved.

In the title compound, [Pd(C4H10NO)Cl(C4H11NO)], the geometry around the Pd atom, which is coordinated by one O, one Cl and two N atoms, is square-planar, with the N atoms trans to each other. One deprotonated N,N-dimethyl-amino- ethanol (dmaeH) mol-ecule acts as a bidentate ligand, while the other is coordinated through the N atom only. The structure displays O - H⋯O hydrogen bonding. © International Union of Crystallography 2007.

Heterobimetallic molecular precursors [Ti4(dmae)6(mu-OH)(mu-O)6Cu6(OAc)9.H2O] (1) and [Zn7(OAc)10(mu-OH)6Cu5(dmae)4Cl4] (2) for the deposition of metal oxide thin films of Cu6Ti4O12 (Cu3TiO4, TiO2) and Cu5Zn7O12 (ZnO, CuO) were prepared by the interaction of Ti(dmae)4 with Cu(OAc)2.2H2O for 1 and tetrameric (N,N-dimethylamino)ethanolatocopper(II) chloride, [(dmae)CuCl]4 [where dmae = (N,N-dimethylamino)ethanolate] with Zn(OAc)2.2H2O (where OAc = acetate) for 2 in dry toluene. Both complexes were characterized by melting point, elemental analysis, Fourier transform IR, fast atom bombardment mass spectrometry, thermal analysis (TGA), and single-crystal X-ray diffraction. TGA and XRD prove that complexes 1 and 2 undergo facile thermal decomposition at 300 and 460 degrees C to form thin films of Cu/Ti and Cu/Zn mixed-metal oxides, respectively. Scanning electron microscopy and XRD of the thin films suggest the formation of impurity-free crystallite mixtures of Cu3TiO4 and TiO2, with average crystallite sizes of 22.2 nm from complex 1 and of ZnO and CuO with average crystallite sizes of 26.1 nm from complex 2.

The title complex, [Co(C2H3O2) 2(C4H11NO)2], was obtained in 70% yield by adding a stoichiometric amount of dmaeH [2-(dimethylamino)ethanol] to Co(C2H3O2)2·4H2O in toluene followed by slow evaporation of the solvent. Two acetate and two dmaeH ligands are coordinated to the CoII center in a slightly distorted octahedral fashion. © 2006 International Union of Crystallography. All rights reserved.

The UVI atom in the title complex, [UO2(C 5H7O2)2 (C4H 8O)], has a pentagonal-bipyramidal geometry. The UVI atom is surrounded by seven O atoms, four of pentane-2,4-dione, one of the tetrahydrofuran ligand and the two uranyl O atoms. © 2006 International Union of Crystallography. All rights reserved.

Heterobimetallic molecular precursors [Co2(acac)2mu-OH)2Cu4(dmae)4Cl4] (2) and [Ni2(acac)2(mu-OH)2Cu4(dmae)4Cl4] (3) [dmaeH = N,N-dimethylaminoethanol and acac = 2,4-pentanedionate] for the deposition of mixed oxide thin films were prepared by the interaction of tetrameric N,N-dimethylaminoethanolato copper(II) chloride, [Cu(dmae)Cl]4 (1) with M(acac)2.xH2O, [M = Co, Ni] in toluene. Both heterobimetallic cage complexes were characterized by melting point, elemental analysis, FT-IR spectroscopy, mass spectrometry, magnetometery, and single-crystal X-ray diffraction. Complexes 2 and 3 are isostructural and crystallize in the monoclinic space group P21/n. A TGA study shows that both complexes undergo controlled thermal decomposition at 450 degrees C to give mixed metal oxides. Solid-state infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and X-ray powder diffraction (XRD) analysis were performed to analyze the chemical composition and surface morphology of the deposited oxide thin films. The results obtained indicate the formation of impurity-free crystalline mixed oxide films with particle sizes ranging from 0.55 to 2.0 microm.

The crystal structure of the title compound, [Pd(C5H 7O2)2], has been redetermined at 100 K using modern equipment, resulting in improved precision compared to the previous study [Knyazeva et al. (1970). Zh. Strukt. Khim. 11, 938-939]. The new measurements reveal that the plane of the 2,4-pentanedionate ligand is tilted by 3.4 (1)° with respect to the PdO4 unit (Pd site symmetry = 1̄). Possible reasons for this bending are examined in terms of previously undiscussed intermolecular interactions. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.

Lorazepam reacts with alizarin sulphonic acid (sodium salt) to give a pink colored complex, after heating at 50°C for 15s having maximum absorbance at 530 nm. The reaction is selective for lorazepam with 0.01 mg/10 ml as visual limit of quantitation and provides a basis for a new spectrophotometric determination. The reaction obeys Beer's Law from 0.01 to 3 mg/10 ml of lorazepam and the relative standard deviation is 0.68%. The quantitative assessments of tolerable amounts of other drugs not interfering are also studied.

Ba(dmae)2 (dmaeH=N,N-dimethylaminoethanol, C4H11NO) reacts with Co(acac)2 (acac=2,4-pentanedionate) to produce the trinuclear coordination complex [Ba2Co(acac)4(dmae)3(dmaeH)] in an 85% yield. Spectroscopic and single-crystal X-ray diffraction experiments indicate that the complex possesses a structure in which two barium atoms and a cobalt atom are bridged by acac and dmae groups. The barium centers are eight and nine coordinate with BaO7N and BaO7N2 coordination spheres while the cobalt is a more regular CoO5N octahedron. This 2:1 heterobimetallic molecular complex was investigated as precursor for the deposition of thin film by AACVD. The film was characterized by SEM and XRD. TGA shows that the complex starts thermal decomposition upon heating in nitrogen atmosphere at 105 degrees C to produce barium cobalt oxide material of a Ba2CoO3 composition with an orthorhombic structure. The synthetic approach detailed here represents a unique route to the formation of a heterobimetallic barium cobalt coordination complex.

The neck-shaft (collodiaphyseal) angle of 320 femora (200 males and 120 females) from indigenes of North-East sub-region of Nigeria were measured. The average collo-diaphyseal angle in males (136.70 degrees +/- 3.905) was greater than in females (126.65 degrees +/- 3.397) with a highly significant statistical difference between both sexes (P < 0.001). Regional variation has also been shown to exist in the neck-shaft angles. Knowledge of the neck-shaft angle in this region would therefore be useful to the surgeon during internal fixation of fractured neck of the femur and also in determining the sex of individual from skeletal remains for medico-legal reasons.