International Journal of Photoenergy The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Synthesis of CuO/Co3O4 Coaxial Heterostructures for Efficient and Recycling Photodegradation Mon, 30 Nov 2015 13:35:50 +0000 The highly efficient CuO/Co3O4 composite photocatalyst with different morphologies has been synthesized directly on Cu wire mesh by controlling the composition of cobalt-containing solid precursors via a simple hydrothermal method. The structure morphology and composition of the composite photocatalyst have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance spectra. The photocatalytic result shows that the CuO/Co3O4 coaxial heterostructure is easy to recycle and exhibit enhanced photodegradation activity for methylene blue compared to single CuO nanorod arrays under full spectrum solar light irradiation. The enhanced photocatalytic efficiency of the composite could be ascribed to the synergistic effect of CuO and Co3O4. This study provides a general and effective method in the fabrication of 1D composition NRs with sound heterojunctions that show enhancement of photocatalytic performance and facility of recycling. R. X. Chen, S. L. Zhu, J. Mao, Z. D. Cui, X. J. Yang, Y. Q. Liang, and Z. Y. Li Copyright © 2015 R. X. Chen et al. All rights reserved. Parameter Optimization of Single-Diode Model of Photovoltaic Cell Using Memetic Algorithm Thu, 26 Nov 2015 07:21:33 +0000 This study proposes a memetic approach for optimally determining the parameter values of single-diode-equivalent solar cell model. The memetic algorithm, which combines metaheuristic and gradient-based techniques, has the merit of good performance in both global and local searches. First, 10 single algorithms were considered including genetic algorithm, simulated annealing, particle swarm optimization, harmony search, differential evolution, cuckoo search, least squares method, and pattern search; then their final solutions were used as initial vectors for generalized reduced gradient technique. From this memetic approach, we could further improve the accuracy of the estimated solar cell parameters when compared with single algorithm approaches. Yourim Yoon and Zong Woo Geem Copyright © 2015 Yourim Yoon and Zong Woo Geem. All rights reserved. New 1,3,4-Oxadiazole Based Photosensitizers for Dye Sensitized Solar Cells (DSSCs) Thu, 26 Nov 2015 06:05:33 +0000 1,3,4-Oxadiazole based photosensitizers with biphenyl, naphthalene, anthracene, and triphenylamine as the electron-donating moiety were synthesized for solar cell applications. In these photosensitizers, cyano groups were introduced as the electron acceptor and the anchor group because of their high electron-withdrawing ability and strong bonding to the semiconductor. Oxadiazole isomers were used as the π-conjugation system, which bridges the donor-acceptor systems. The electrochemical and optical properties of the sensitizers were investigated both in their native form and upon incorporation into dye sensitized solar cells. The results of UV-visible absorption spectroscopy, electrochemical impedance spectroscopic measurements, and photocurrent voltage characteristics indicate that 1,3,4-oxadiazole pi-spacer with the anthracene moiety has the highest efficiency of 2.58%. Density functional theory was employed to optimize the structures of the sensitizers and the TiO2 cluster. Umer Mehmood, Ibnelwaleed A. Hussein, and Muhammad Daud Copyright © 2015 Umer Mehmood et al. All rights reserved. Evaluation of La-Doped Mesoporous Bioactive Glass as Adsorbent and Photocatalyst for Removal of Methylene Blue from Aqueous Solution Thu, 19 Nov 2015 10:07:04 +0000 A series of La-doped mesoporous bioactive glass (BG-La) materials with excellent biosafety and hypotoxicity have been prepared and tested as adsorbent. The study was aimed to evaluate the possibility of utilizing BG-La for the adsorptive removal of methylene blue (MB) from aqueous solution and test the adsorption and desorption behavior of this new material. The process parameters affecting adsorption behaviors such as pH, contact time, and initial concentration and the photocatalytic degradation of MB were systematically investigated. The result showed that BG-La had excellent removal rate (R) of MB, and BG-La showed better photocatalytic effect than undoped mesoporous bioactive glass (BG). Furthermore, the MB loaded BG-La was easily desorbed with acid solution due to its electronegativity and mesoporous structure. The result indicated that these materials can be employed as candidates for removal of dye pollutant owing to their high removal rate, excellent photocatalytic effect, desorption performance, and their reusability. Liying Li, Huanrui Shi, Lu Chen, Qianxuan Yuan, Xi Chen, and Weijian Lin Copyright © 2015 Liying Li et al. All rights reserved. Improved Photocatalytic Performance of a Novel Fe3O4@SiO2/Bi2SiO5 Hierarchical Nanostructure with Magnetic Recoverability Tue, 17 Nov 2015 14:21:21 +0000 Magnetic Fe3O4@SiO2/Bi2SiO5 composites with a novel hierarchical nanostructure were synthesized by sol-gel and hydrothermal methods and were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance spectroscopy (UV-vis DRS). It was found that the introduction of Fe3O4@SiO2 could turn the morphology of Bi2SiO5 from close-grained slab to hollow hierarchical architecture with fabric-structure. The Fe3O4@SiO2/Bi2SiO5 composite showed enhanced photodegradation efficiency for the degradation of reactive brilliant red dye (X-3B) in aqueous solution under simulated sunlight irradiation, as compared with that of commercial P25. In addition, the Fe3O4@SiO2/Bi2SiO5 composite exhibited good magnetic recoverability and excellent photocatalytic stability (no obvious activity loss after recycling tests). Xinxin Zhang, Xiaoli Dong, Baiyu Leng, Hongchao Ma, and Xiufang Zhang Copyright © 2015 Xinxin Zhang et al. All rights reserved. Theoretical and Experimental Optical Evaluation and Comparison of Symmetric 2D CPC and V-Trough Collector for Photovoltaic Applications Tue, 17 Nov 2015 13:32:28 +0000 This paper presents theoretical and experimental optical evaluation and comparison of symmetric Compound Parabolic Concentrator (CPC) and V-trough collector. For direct optical properties comparison, both concentrators were deliberately designed to have the same geometrical concentration ratio (1.96), aperture area, absorber area, and maximum concentrator length. The theoretical optical evaluation of the CPC and V-trough collector was carried out using a ray-trace technique while the experimental optical efficiency and solar energy flux distributions were analysed using an isolated cell PV module method. Results by simulation analysis showed that for the CPC, the highest optical efficiency was 95% achieved in the interval range of 0° to ±20° whereas the highest outdoor experimental optical efficiency was 94% in the interval range of 0° to ±20°. For the V-tough collector, the highest optical efficiency for simulation and outdoor experiments was about 96% and 93%, respectively, both in the interval range of 0° to ±5°. Simulation results also showed that the CPC and V-trough exhibit higher variation in non-illumination intensity distributions over the PV module surface for larger incidence angles than lower incidence angles. On the other hand, the maximum power output for the cells with concentrators varied depending on the location of the cell in the PV module. Damasen Ikwaba Paul Copyright © 2015 Damasen Ikwaba Paul. All rights reserved. TiO2/Halloysite Composites Codoped with Carbon and Nitrogen from Melamine and Their Enhanced Solar-Light-Driven Photocatalytic Performance Mon, 16 Nov 2015 16:23:16 +0000 Carbon (C) and nitrogen (N) codoped anatase TiO2/amorphous halloysite nanotubes (C+N-TiO2/HNTs) were fabricated using melamine as C and N source. The samples prepared by different weight ratios of melamine and TiO2 were investigated by X-ray diffraction (XRD) and UV-vis diffuse reflectance spectrometer. It is shown that the doping amounts of C and N could influence the photocatalytic performance of as-prepared composites. When the weight ratio of melamine/TiO2 is 4.5, the C+N-TiO2/HNTs exhibited the best photocatalytic degradation efficiency of methyl blue (MB) under solar light irradiation. The obtained C+N-TiO2/HNTs were characterized by transmission electron microscopy (TEM), N2 adsorption-desorption isotherm (BET), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrum (FT-IR). The results showed that the aggregation was effectively reduced, and TiO2 nanoparticles could be uniformly deposited on the surface of HNTs. This leads to an increase of their specific surface area. XPS and FT-IR analyses indicated TiO2 particles were doped successfully with C and N via the linkage of the Ti–O–N, O–Ti–N, and Ti–O–C. Photocatalytic experiments showed that C+N-TiO2/HNTs had higher degradation efficiency of MB than TiO2/HNTs. This makes the composite a potential candidate for the photocatalytic wastewater treatment. Pengcheng Yao, Shuhui Zhong, and Zhurui Shen Copyright © 2015 Pengcheng Yao et al. All rights reserved. Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes Mon, 16 Nov 2015 12:50:19 +0000 Indium tin oxide (ITO) thin films were grown on glass substrates by direct current (DC) reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were  cm−3,  cm2/Vs,  Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm) of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS) solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells. Chuan Lung Chuang, Ming Wei Chang, Nien Po Chen, Chung Chiang Pan, and Chung Ping Liu Copyright © 2015 Chuan Lung Chuang et al. All rights reserved. Substrate Temperature Effect on Charge Transport Performance of ZnO Electron Transport Layer Prepared by a Facile Ultrasonic Spray Pyrolysis in Polymer Solar Cells Mon, 16 Nov 2015 08:19:36 +0000 A novel ultrasonic spray pyrolysis for high-quality ZnO films based on zinc-ammonia solution was achieved in air. To investigate the structural and optical properties as well as the performance of polymer solar cells (PSCs), ZnO films at different substrate temperatures and thicknesses were prepared. The performance of poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) based PSC was found to be improved due to the ZnO films. The crystal structure and roughness of the ZnO films fabricated at different temperatures were found to affect the performance of PSCs. The optimized power conversion efficiency was found to be maximum for PSCs with ZnO films prepared at 200°C. The growth process of these ZnO films is very simple, cost-effective, and compatible for larger-scale PSC preparation. The precursor used for spray pyrolysis is environmentally friendly and helps to achieve ZnO film preparation at a relative low temperature. Jiang Cheng, Rong Hu, Qi Wang, Chengxi Zhang, Zhou Xie, Zhangwen Long, Xin Yang, and Lu Li Copyright © 2015 Jiang Cheng et al. All rights reserved. Highlighting Photocatalytic H2-Production from Natural Seawater and the Utilization of Quasi-Photosynthetic Absorption as Two Ultimate Solutions for CO2 Mitigation Wed, 11 Nov 2015 11:55:35 +0000 This paper reviews five potential solutions for CO2 mitigation and theoretically analyzes related outstanding questions. Emission trading under the global mitigation objectives and policies is in dilemma because reducing emission while utilizing fossil fuels is a difficult balance. CO2 capture and sequestration (CCS) technique offers a comprehensive solution, but it is risky and expensive. Analyses of the 100% renewable energy plan suggest hydrogen as a fuel of zero CO2 emission. Photocatalytic splitting of natural seawater can be an ultimate scheme for the hydrogen production, providing that the associated technological constraints would be overcome. Soil CO2 absorption in the arid regions (terms such absorption “quasi-photosynthetic absorption”) implies a potential solution, but the kinetics and overall importance are undetermined. Further investigations of these unresolved issues are strongly needed to realize the global CO2 mitigation target. Comparing the five potential solutions, photocatalytic H2-production from natural seawater and the utilization of quasi-photosynthetic absorption are highlighted as two ultimate solutions. Wenfeng Wang, Xi Chen, Heng Zhang, Changqing Jing, Yifan Zhang, and Bo Yan Copyright © 2015 Wenfeng Wang et al. All rights reserved. Method to Calculate the Electricity Generated by a Photovoltaic Cell, Based on Its Mathematical Model Simulations in MATLAB Tue, 10 Nov 2015 13:36:13 +0000 This paper presents a practical method for calculating the electrical energy generated by a PV panel (kWhr) through MATLAB simulations based on the mathematical model of the cell, which obtains the “Mean Maximum Power Point” (MMPP) in the characteristic - curve, in response to evaluating historical climate data at specific location. This five-step method calculates through MMPP per day, per month, or per year, the power yield by unit area, then electrical energy generated by PV panel, and its real conversion efficiency. To validate the method, it was applied to Sewage Treatment Plant for a Group of Drinking Water and Sewerage of Yucatan (JAPAY), México, testing 250 Wp photovoltaic panels of five different manufacturers. As a result, the performance, the real conversion efficiency, and the electricity generated by five different PV panels in evaluation were obtained and show the best technical-economic option to develop the PV generation project. Carlos Morcillo-Herrera, Fernando Hernández-Sánchez, and Manuel Flota-Bañuelos Copyright © 2015 Carlos Morcillo-Herrera et al. All rights reserved. The Effects of Nonuniform Illumination on the Electrical Performance of a Single Conventional Photovoltaic Cell Tue, 10 Nov 2015 07:00:09 +0000 Photovoltaic (PV) concentrators are a promising approach for lowering PV electricity costs in the near future. However, most of the concentrators that are currently used for PV applications yield nonuniform flux profiles on the surface of a PV module which in turn reduces its electrical performance if the cells are serially connected. One way of overcoming this effect is the use of PV modules with isolated cells so that each cell generates current that is proportional to the energy flux absorbed. However, there are some cases where nonuniform illumination also exists in a single cell in an isolated cells PV module. This paper systematically studied the effect of nonuniform illumination on various cell performance parameters of a single monocrystalline standard PV cell at low and medium energy concentration ratios. Furthermore, the effect of orientation, size, and geometrical shapes of nonuniform illumination was also investigated. It was found that the effect of nonuniform illumination on various PV cell performance parameters of a single standard PV cell becomes noticeable at medium energy flux concentration whilst the location, size, and geometrical shape of nonuniform illumination have no effect on the performance parameters of the cell. Damasen Ikwaba Paul, Mervyn Smyth, Aggelos Zacharopoulos, and Jayanta Mondol Copyright © 2015 Damasen Ikwaba Paul et al. All rights reserved. Effects of Sulfurization Pressure on the Conversion Efficiency of Cosputtered Cu2ZnSnS4 Thin Film Solar Cells Sun, 08 Nov 2015 12:44:13 +0000 We report herein Cu2ZnSnS4 (CZTS) thin film solar cells with 6.75% conversion efficiency, without an antireflection coating. The CZTS precursors have been prepared by cosputtering using three different targets on Mo-coated substrates: copper (Cu), tin sulfide (SnS), and zinc (Zn). The postsulfurization was carried out at different pressures in a H2S/N2 environment at 550°C for one hour. A comparative study on the performances of solar cells with CZTS absorber layers prepared at different sulfurization pressures was carried out. The device efficiency of 1.67% using CZTS absorber and low pressure sulfurization is drastically improved, to an efficiency of 6.75% with atmospheric pressure sulfurization. Arun Khalkar, Kwang-Soo Lim, Seong-Man Yu, Dong-Wook Shin, Tae-Sik Oh, and Ji-Beom Yoo Copyright © 2015 Arun Khalkar et al. All rights reserved. Price-Efficiency Relationship for Photovoltaic Systems on a Global Basis Sun, 08 Nov 2015 06:04:13 +0000 Solar energy is the most abundant, useful, efficient, and environmentally friendly source of renewable energy. In addition, in recent years, the capacity of photovoltaic electricity generation systems has increased exponentially throughout the world given an increase in the economic viability and reliability of photovoltaic systems. Moreover, many studies state that photovoltaic power systems will play a key role in electricity generation in the future. When first produced, photovoltaic systems had short lifetimes. Currently, through development, the technology lifecycle of photovoltaic systems has increased to 20–25 years. Studies showed that photovoltaic systems would be broadly used in the future, a conclusion reached by considering the rapidly decreasing cost of photovoltaic systems. Because price analysis is very important for energy marketing, in this study, a review of the cost potential factors on photovoltaic panels is realized and the expected cost potential of photovoltaic systems is examined considering numerous studies. Mehmet Sait Cengiz and Mehmet Salih Mamiş Copyright © 2015 Mehmet Sait Cengiz and Mehmet Salih Mamiş. All rights reserved. New TiO2/DSAT Immobilization System for Photodegradation of Anionic and Cationic Dyes Thu, 05 Nov 2015 08:44:40 +0000 A new immobilized TiO2 technique was prepared by coating TiO2 solution onto double-sided adhesive tape (DSAT) as a thin layer binder without adding any organic additives. Glass plate was used as support material to immobilized TiO2/DSAT. Two different charges of dyes were applied, namely, anionic reactive red 4 (RR4) and cationic methylene blue (MB) dyes. Photocatalytic degradation of RR4 and MB dyes was observed under immobilized TiO2/DSAT with the degradation rate slightly lower and higher, respectively, compared with TiO2 in suspension mode. It was observed that DSAT is able to provide a very strong intact between glass and TiO2 layers thus making the reusability of immobilized TiO2/DSAT be up to 30 cycles. In fact, a better photodegradation activity was observed by number of cycles due to increasing formation of pores on TiO2 surface observed by SEM analysis. Wan Izhan Nawawi Wan Ismail, S. K. Ain, R. Zaharudin, Ali H. Jawad, M. A. M. Ishak, Khudzir Ismail, and Sudirman Sahid Copyright © 2015 Wan Izhan Nawawi Wan Ismail et al. All rights reserved. Electrical and Thermal Performance Analysis for a Highly Concentrating Photovoltaic/Thermal System Wed, 04 Nov 2015 11:14:13 +0000 A 30 kW highly concentrating photovoltaic/thermal (HCPV/T) system has been constructed and tested outdoors. The HCPV/T system consists of 32 modules, each of which consists of point-focus Fresnel lens and triple-junction solar cells with a geometric concentrating ratio of 1090x. The modules are connected to produce both electrical and thermal energy. Performance analysis has been conducted from the viewpoint of thermodynamics. The experimental results show that highest photovoltaic efficiency of 30% and instantaneous thermal efficiency of 30% can be achieved at the same time, which means the total solar energy conversion efficiency of the HCPV/T system is higher than 60%. The photovoltaic efficiency increases with direct irradiance when the direct irradiance is below 580 W/m2, but it remains nearly unchanged when the direct irradiation is higher than 580 W/m2. The instantaneous thermal efficiency decreases during water heating process. However, the electrical performance of the system is not affected obviously by water temperature. Highest exergetic efficiency of 35.4% can be produced by the HCPV/T system. The exergetic efficiency is mainly affected by irradiation level, which is similar to the characteristics of photovoltaic performance. Ning Xu, Jie Ji, Wei Sun, Wenzhu Huang, and Zhuling Jin Copyright © 2015 Ning Xu et al. All rights reserved. PID Testing Method Suitable for Process Control of Solar Cells Mass Production Tue, 03 Nov 2015 14:26:29 +0000 Voltage bias of several hundred volts which are applied between solar cells and module frames may lead to significant power losses, so-called potential-induced degradation (PID), in normal photovoltaic (PV) installations system. Modules and minimodules are used to conduct PID test of solar cells. The test procedure is time consuming and of high cost, which cannot be used as process monitoring method during solar cells fabrication. In this paper, three kinds of test including minimodule, , and V-Q test are conducted on solar cells or wafers with SiNx of different refractive index. All comparisons between test results of , V-Q, and minimodule tests have shown equal results. It is shown that test can be used as quality inspection of solar cells and V-Q test of coated wafer can be used as process control of solar cells. Xianfang Gou, Xiaoyan Li, Su Zhou, Shaoliang Wang, Weitao Fan, and Qingsong Huang Copyright © 2015 Xianfang Gou et al. All rights reserved. Synthesis, Characterization, and Electronic Structure Studies of Cubic Bi1.5ZnTa1.5O7 for Photocatalytic Applications Sun, 01 Nov 2015 10:01:35 +0000 Bi1.5ZnTa1.5O7 (BZT) has been synthesized using an alkoxide based sol-gel reaction route. The evolution of the phases produced from the alkoxide precursors and their properties have been characterized as function of temperature using a combination of thermogravimetric analysis (TGA) coupled with mass spectrometry (MS), infrared emission spectrometry (IES), X-ray diffraction (XRD), ultraviolet and visible (UV-Vis) spectroscopy, Raman spectroscopy, and N2 adsorption/desorption isotherms. The lowest sintering temperature (600°C) to obtain phase pure BZT powders with high surface area (14.5 m2/g) has been determined from the thermal decomposition and phase analyses. The photocatalytic activity of the BZT powders has been tested for the decolorization of organic azo-dye and found to be photoactive under UV irradiation. The electronic band structure of the BZT has been investigated using density functional theory (DFT) calculations to determine the band gap energy (3.12 eV) and to compare it with experimental band gap (3.02 eV at 800°C) from optical absorption measurements. An excellent match is obtained for an assumption of Zn cation substitutions at specifically ordered sites in the BZT structure. Ganchimeg Perenlei, Jose A. Alarco, Peter C. Talbot, and Wayde N. Martens Copyright © 2015 Ganchimeg Perenlei et al. All rights reserved. Experimental Investigation of the Effects of Partial Shading on Photovoltaic Cells’ Electrical Parameters Thu, 29 Oct 2015 09:26:35 +0000 The short-circuit current (), the open-circuit voltage (), and the maximum power point (, ) of monocrystalline and multicrystalline silicon solar cells under three kinds of partial shading patterns have been investigated experimentally. The partial shades are, respectively, the nine shelter locations by 1 cm × 1 cm black card, the six shelter locations by 2 cm × 1 cm black card, and the center shelters with isosceles triangle, circle, square, and two rectangles black cards whose areas are 2 cm2. Firstly, the results show that the partial shading causes disproportional high losses on those parameters of both cells but will have a minimal effect on . Secondly, it is found that those parameters of the monocrystalline cell are less dependent on the shading than that of the multicrystalline cell. Thirdly, it is noted that and of both cells will be decreasing dramatically as a rectangular black shading card with a long side parallel to cell’s finger, compared with that normal to cell’s finger. Finally, it can be seen that the effects of shading on the electrical parameters of both cells will be suppressed when the border lines of shading match the size of the shaded cell. W. B. Xiao, F. Y. Hu, H. M. Zhang, and H. M. Wu Copyright © 2015 W. B. Xiao et al. All rights reserved. Morphology versus Vertical Phase Segregation in Solvent Annealed Small Molecule Bulk Heterojunction Organic Solar Cells Wed, 28 Oct 2015 11:36:34 +0000 The deep study of solvent annealed small molecules bulk heterojunction organic solar cells based on DPP(TBFu)2 : PC60BM blend is carried out. To reveal the reason of the solvent annealing advantage over the thermal one, capacitance-voltage measurements were applied. It was found that controlling the vertical phase segregation in the solar cells a high fullerene population in the vicinity of the cathode could be achieved. This results in increase of the shunt resistance of the cell, thus improving the light harvesting efficiency. Alexander Kovalenko, Darina Stoyanova, Jan Pospisil, Ivaylo Zhivkov, Ladislav Fekete, Daniela Karashanova, Irena Kratochvílová, Martin Vala, and Martin Weiter Copyright © 2015 Alexander Kovalenko et al. All rights reserved. Technique for Outdoor Test on Concentrating Photovoltaic Cells Tue, 27 Oct 2015 11:50:57 +0000 Outdoor experimentation of solar cells is essential to maximize their performance and to assess utilization requirements and limits. More generally tests with direct exposure to the sun are useful to understand the behavior of components and new materials for solar applications in real working conditions. Insolation and ambient factors are uncontrollable but can be monitored to know the environmental situation of the solar exposure experiment. A parallel characterization of the photocells can be performed in laboratory under controllable and reproducible conditions. A methodology to execute solar exposure tests is proposed and practically applied on photovoltaic cells for a solar cogeneration system. The cells are measured with concentrated solar light obtained utilizing a large Fresnel lens mounted on a sun tracker. Outdoor measurements monitor the effects of the exposure of two multijunction photovoltaic cells to focused sunlight. The main result is the continuous acquisition of the - (voltage-current) curve for the cells in different conditions of solar concentration and temperature of exercise to assess their behavior. The research investigates electrical power extracted, efficiency, temperatures reached, and possible damages of the photovoltaic cell. Paola Sansoni, Daniela Fontani, Franco Francini, David Jafrancesco, Giacomo Pierucci, and Maurizio De Lucia Copyright © 2015 Paola Sansoni et al. All rights reserved. Glazed PVT Collector with Polysiloxane Encapsulation of PV Cells: Performance and Economic Analysis Mon, 26 Oct 2015 09:40:52 +0000 Development of a new concept of glazed PVT collector based on temperature resistant polysiloxane encapsulation material is presented together with the results from experimental testing and modelling. Performance and economic analysis in 4 different European climates has been done to derive the competitive price of the PVT collector concepts with main focus on the glazed PVT collector under development. Results have shown that specific market price 400 to 500 EUR/m2 for the glazed PVT collector should not be exceeded in order to become competitive with conventional combination of photothermal and photovoltaic collectors. Tomas Matuska, Borivoj Sourek, Vladimir Jirka, and Nikola Pokorny Copyright © 2015 Tomas Matuska et al. All rights reserved. Aggregation Behavior of Some Asymmetric Porphyrins versus Basic Biological Tests Response Tue, 20 Oct 2015 11:37:01 +0000 Fractal analysis of free bases porphyrins was computed on atomic force microscopy (AFM) micrographs using two different methods: the correlation function method and the variable length scale method. The correlation function method provides fractal dimension only for short scale range; results indicate that only few images have fractal properties for short ranges; for the rest of them, no fractal dimension was found using the correlation function method. The variable length scale method occur information for long range scaling. All samples have fractal properties at higher scaling range. For three samples the correlation function method leads to the same fractal dimension as the variable length scale method and scaling ranges for both methods overlap. Results show the necessity to use both methods to describe the fractal properties of AB3  meso-porphyrins that may be used to predict their relative cell localization. In order to emphasize the influence of fractal and textural properties the results regarding their self-similarity and texture/morphology were further compared with their behavior in biological assessment, that is, functionality of some Jurkat cell lines. Radu Socoteanu, Mihai Anastasescu, Anabela Oliveira, Gianina Dobrescu, Rica Boscencu, and Carolina Constantin Copyright © 2015 Radu Socoteanu et al. All rights reserved. Enhanced Photocatalytic Property of Cu Doped Sodium Niobate Tue, 20 Oct 2015 06:49:26 +0000 We investigate the photocatalytic activity of Cu doped NaNbO3 powder sample prepared by the modified polymer complex method. The photocatalytic activity of hydrogen evolution from methanol aqueous solution was improved by Cu 2.6 at% doping. The photocatalytic degradation of rhodamine B (RhB) under visible light irradiation was enhanced in comparison with pristine NaNbO3. Cu introduction improved the adsorption property of NaNbO3, judging from the Fourier transform infrared spectra. Moreover, the ultraviolet light excitation in Cu doped sample would accelerate the mineralized process. Jianbin Xu, Feng Zhang, Bingyang Sun, Yingge Du, Guoqiang Li, and Weifeng Zhang Copyright © 2015 Jianbin Xu et al. All rights reserved. Study on Concentrating Characteristics of a Solar Parabolic Dish Concentrator within High Radiation Flux Mon, 19 Oct 2015 07:16:05 +0000 Concentrating characteristics of the sunlight have an important effect on the optical-thermal conversion efficiency of solar concentrator and the application of the receiver. In this paper, radiation flux in the focal plane and the receiver with three focal lengths has been investigated based on Monte Carlo ray-tracing method. At the same time, based on the equal area-height and equal area-diameter methods to design four different shape receivers and numerical simulation of radiation flux distribution characteristics have also been investigated. The results show that the radiation flux in the focal plane increases with decreasing of the focal length and the diameter of the light spot increases with increasing of the focal length. The function of the position with a maximum of radiation flux has been obtained according to the numerical results. The results also show that the radiation flux distribution of cylindrical receiver has the best performance in all four receivers. The results can provide a reference for future design and application of concentrating solar power. Qianjun Mao, Liya Zhang, and Hongjun Wu Copyright © 2015 Qianjun Mao et al. All rights reserved. Study on the Optical Properties of Triangular Cavity Absorber for Parabolic Trough Solar Concentrator Mon, 19 Oct 2015 06:27:36 +0000 A theoretical analytical method for optical properties of cavity absorber was proposed in this paper and the optical design software TracePro was used to analyze the optical properties of triangular cavity absorber. It was found that the optimal optical properties could be achieved with appropriate aperture width, depth-to-width ratio, and offset distance from focus of triangular cavity absorber. Based on the results of orthogonal experiment, the optimized triangular cavity absorber was designed. Results showed that the standard deviation of irradiance and optical efficiency of optimized designed cavity absorber were 30528 W/m2 and 89.23%, respectively. Therefore, this study could offer some valuable references for designing the parabolic trough solar concentrator in the future. Fei Chen, Ming Li, Reda Hassanien Emam Hassanien, Xi Luo, Yongrui Hong, Zhikang Feng, Mengen Ji, and Peng Zhang Copyright © 2015 Fei Chen et al. All rights reserved. Wetting and Photocatalytic Properties of TiO2 Nanotube Arrays Prepared via Anodic Oxidation of E-Beam Evaporated Ti Thin Films Sun, 18 Oct 2015 14:34:06 +0000 TiO2 nanotube arrays (TNAs) are fabricated on quartz substrate by anodizing E-beam evaporated Ti films. E-beam evaporated Ti films are directly anodized at various anodizing voltages ranging from 20 to 45 V and their morphological, wetting, and photocatalytic properties are examined. The photocatalytic activity of the prepared TNAs is evaluated by the photodecomposition of methylene blue under UV illumination. The TNAs prepared at an anodizing voltage of 30 V have a high roughness of 30.1 nm and a low water contact angle of 7.5°, resulting in a high photocatalytic performance. The surface roughness of the TNAs is found to correlate inversely with the water contact angle. High roughness (i.e., high surface area), which leads to high hydrophilicity, is desirable for effective photocatalytic activity. Soon Wook Kim, Hong Ki Kim, Jong Won Yun, Eui Jung Kim, and Sung Hong Hahn Copyright © 2015 Soon Wook Kim et al. All rights reserved. A Model for Hourly Solar Radiation Data Generation from Daily Solar Radiation Data Using a Generalized Regression Artificial Neural Network Tue, 13 Oct 2015 12:34:15 +0000 This paper presents a model for predicting hourly solar radiation data using daily solar radiation averages. The proposed model is a generalized regression artificial neural network. This model has three inputs, namely, mean daily solar radiation, hour angle, and sunset hour angle. The output layer has one node which is mean hourly solar radiation. The training and development of the proposed model are done using MATLAB and 43800 records of hourly global solar radiation. The results show that the proposed model has better prediction accuracy compared to some empirical and statistical models. Two error statistics are used in this research to evaluate the proposed model, namely, mean absolute percentage error and root mean square error. These values for the proposed model are 11.8% and −3.1%, respectively. Finally, the proposed model shows better ability in overcoming the sophistic nature of the solar radiation data. Tamer Khatib and Wilfried Elmenreich Copyright © 2015 Tamer Khatib and Wilfried Elmenreich. All rights reserved. Quantum Sized Zinc Oxide Immobilized on Bentonite Clay and Degradation of C.I. Acid Red 35 in Aqueous under Ultraviolet Light Thu, 08 Oct 2015 07:05:43 +0000 Nano-ZnO supported on bentonite was prepared to form composite photocatalyst by sol-gel method. The photocatalyst was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscope (TEM). C.I. Acid Red 35 was used as simulating contaminant to be treated by ultraviolet light synergistic with nano-ZnO/bentonite. The results show that 5.7 nm ZnO particle was acquired and uniformly dispersed on the surface of the bentonite at calcination temperature of 200°C. The removal of C.I. Acid Red 35 could reach 84.9% after 200 min under optimum ZnO/bentonite dosage of 0.6 g L−1. The 60% ZnO content in ZnO/bentonite composite exhibited a great photocatalytic activity to treat C.I. Acid Red 35. The photocatalytic process followed pseudo-first-order kinetics and the best apparent rate constant was 0.00927 min−1 with correlation coefficient (R2) of above 0.98. Hang Xu, Dandan Zhang, Airong Xu, Fengmin Wu, and Renqiang Cao Copyright © 2015 Hang Xu et al. All rights reserved. New Architecture towards Ultrathin CdTe Solar Cells for High Conversion Efficiency Mon, 05 Oct 2015 10:46:24 +0000 Solar Cell Capacitance Simulator in 1 Dimension (SCAPS-1D) is used to investigate the possibility of realizing ultrathin CdTe based solar cells with high and stable conversion efficiency. In the first step, we modified the conventional cell structure by substituting the CdS window layer with a CdS:O film having a wide band gap ranging from 2.42 to 3.17 eV. Thereafter, we simulated the quantum efficiency, as well as the parameters of J-V characteristics, and showed how the thickness of CdS:O layer influences output parameters of Glass/SnO2/ZTO/CdS:O/CdT/CdTe/Ni reference cell. High conversion efficiency of 17.30% has been found using CdT () and CdTe layers of thickness 15 nm and 4 μm, respectively. Secondly, we introduced a BSR layer between the absorber layer and back metal contact, which led to Glass/SnO2/ZTO/CdS:O/CdT/CdTe/BSR/Ni configuration. We found that a few nanometers (about 5 nm) of CdT layer is sufficient to obtain high conversion efficiency. For BSR layer, different materials with large band gap, such as ZnTe, Cu2Te, and p+-CdTe, have been used in order to reduce minority carrier recombination at the back contact. When ZnTe is used, high conversion efficiency of 21.65% and better stability are obtained, compared to other BSR. A. Teyou Ngoupo, S. Ouédraogo, F. Zougmoré, and J. M. B. Ndjaka Copyright © 2015 A. Teyou Ngoupo et al. All rights reserved.