International Journal of Photoenergy http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Analysis of Different Series-Parallel Connection Modules for Dye-Sensitized Solar Cell by Electrochemical Impedance Spectroscopy Thu, 26 May 2016 06:35:30 +0000 http://www.hindawi.com/journals/ijp/2016/6595639/ The internal impedances of different dye-sensitized solar cell (DSSC) models were analyzed by electrochemical impedance spectrometer (EIS) with an equivalent circuit model. The Nyquist plot was built to simulate the redox reaction of internal device at the heterojunction. It was useful to analyze the component structure and promote photovoltaic conversion efficiency of DSSC. The impedance of DSSC was investigated and the externally connected module assembly was constructed utilizing single cells on the scaled-up module. According to the experiment results, the impedance was increased with increasing cells connected in series. On the contrary, the impedance was decreased with increasing cells connected in parallel. Jung-Chuan Chou, Chin-Hui Huang, Yi-Hung Liao, Yu-Jen Lin, Chia-Ming Chu, and Yu-Hsun Nien Copyright © 2016 Jung-Chuan Chou et al. All rights reserved. Influence Applied Potential on the Formation of Self-Organized ZnO Nanorod Film and Its Photoelectrochemical Response Tue, 24 May 2016 09:45:46 +0000 http://www.hindawi.com/journals/ijp/2016/1413072/ The present paper reports on the facile formation of ZnO nanorod photocatalyst electrodeposited on Zn foil in the production of hydrogen gas via water photoelectrolysis. Based on the results, ZnO nanorod films were successfully grown via electrochemical deposition in an optimum electrolyte set of 0.5 mM zinc chloride and 0.1 M potassium chloride at pH level of 5-6 and electrochemical deposition temperature of around 70°C. The study was also conducted at a very low stirring rate with different applied potentials. Applied potential was one of the crucial aspects in the formation of self-organized ZnO nanorod film via control of the field-assisted dissolution and field-assisted deposition rates during the electrochemical deposition process. Interestingly, low applied potentials of 1 V during electrochemical deposition produced a high aspect ratio and density of self-organized ZnO nanorod distribution on the Zn substrate with an average diameter and length of ~37.9 nm and ~249.5 nm, respectively. Therefore, it exhibited a high photocurrent density that reached 17.8 mA/cm2 under ultraviolet illumination and 12.94 mA/cm2 under visible illumination. This behaviour was attributed to the faster transport of photogenerated electron/hole pairs in the nanorod’s one-dimensional wall surface, which prevented backward reactions and further reduced the number of recombination centres. Nur Azimah Abd Samad, Chin Wei Lai, and Sharifah Bee Abd Hamid Copyright © 2016 Nur Azimah Abd Samad et al. All rights reserved. Evaluation of the Antimicrobial Activity of Nanostructured Materials of Titanium Dioxide Doped with Silver and/or Copper and Their Effects on Arabidopsis thaliana Sun, 22 May 2016 11:56:05 +0000 http://www.hindawi.com/journals/ijp/2016/8060847/ Nanostructured materials (NSMs) of silver (Ag@TiO2) and copper (TiO2-Cu2+) doped titanium dioxide were synthesized, fully characterized, and evaluated for their antimicrobial efficiency and effects on Arabidopsis thaliana. The NSMs were prepared using an environmentally benign route. The physicochemical properties of the materials were determined with analytical techniques. These materials are active under visible light, exhibit a small size (10–12 nm), are crystalline (anatase), and liberate metal ions (Ag+ and Cu2+) in solution. Microbicide activity was observed in E. coli C600 and S. cerevisiae W303 strains treated with several concentrations of Ag@TiO2 and TiO2-Cu2+, radiated and nonradiated, and after different times. Higher inactivation was achieved with Ag@TiO2 in E. coli, with value of log inactivation of 2.2 with 0.5 mg/mL after 4 h, than in S. cerevisiae, with a log inactivation of 2.6 with 10 mg/mL after 24 h. The impact of these NSMs in plants was evaluated in Arabidopsis thaliana Col-0 strain exposed to such materials at different conditions and concentrations, and physical and biochemical effects were analyzed. Seeds exposed to NSMs did not show effects on germination and growth. However, seedlings treated with these materials modified their growth and their total chlorophyll content. Cristina Garcidueñas-Piña, Iliana E. Medina-Ramírez, Plinio Guzmán, Roberto Rico-Martínez, José Francisco Morales-Domínguez, and Isidoro Rubio-Franchini Copyright © 2016 Cristina Garcidueñas-Piña et al. All rights reserved. Photostability and Photostabilization of Drugs and Drug Products Tue, 17 May 2016 13:15:39 +0000 http://www.hindawi.com/journals/ijp/2016/8135608/ Photostability studies of drugs and drug products are an integral part of the product development process in the pharmaceutical industry. These studies are carried out to ensure quality, efficacy, and safety of the formulated products during manufacture, storage, and use. This review deals with the concept of photostability and related aspects and the literature available in the field. It highlights the role of the photochemistry in the photostability studies, describes the functional groups important for the photoreactivity of drugs, explains photophysical processes, and deals with the kinetics of photochemical reactions. The various modes of photodegradation of drugs with examples of selected compounds are presented. The biological consequences of the effect of light on the drug degradation are described. The photostability testing of drugs and drug products and the requirements under ICH guideline are discussed. Some information on the packaging requirements for the formulated products is provided. The various methods used for the photostabilization of solid and liquid dosage forms are also discussed. Iqbal Ahmad, Sofia Ahmed, Zubair Anwar, Muhammad Ali Sheraz, and Marek Sikorski Copyright © 2016 Iqbal Ahmad et al. All rights reserved. A Novel Maximum Power Point Tracking Algorithm Based on Glowworm Swarm Optimization for Photovoltaic Systems Thu, 05 May 2016 11:14:50 +0000 http://www.hindawi.com/journals/ijp/2016/4910862/ In order to extract the maximum power from PV system, the maximum power point tracking (MPPT) technology has always been applied in PV system. At present, various MPPT control methods have been presented. The perturb and observe (P&O) and conductance increment methods are the most popular and widely used under the constant irradiance. However, these methods exhibit fluctuations among the maximum power point (MPP). In addition, the changes of the environmental parameters, such as cloud cover, plant shelter, and the building block, will lead to the radiation change and then have a direct effect on the location of MPP. In this paper, a feasible MPPT method is proposed to adapt to the variation of the irradiance. This work applies the glowworm swarm optimization (GSO) algorithm to determine the optimal value of a reference voltage in the PV system. The performance of the proposed GSO algorithm is evaluated by comparing it with the conventional P&O method in terms of tracking speed and accuracy by utilizing MATLAB/SIMULINK. The simulation results demonstrate that the tracking capability of the GSO algorithm is superior to that of the traditional P&O algorithm, particularly under low radiance and sudden mutation irradiance conditions. Wenhui Hou, Yi Jin, Changan Zhu, and Guiqiang Li Copyright © 2016 Wenhui Hou et al. All rights reserved. Numerical Investigations and Analysis of Cu2ZnSnS4 Based Solar Cells by SCAPS-1D Tue, 03 May 2016 08:53:19 +0000 http://www.hindawi.com/journals/ijp/2016/2152018/ This paper reports numerical investigation, using SCAPS-1D program, of the influence of Cu2ZnSnS4 (the so-called CZTS) material features such as thickness, holes, and defects densities on the performances of ZnO:Al/i-ZnO/CdS/CZTS/Mo solar cells structure. We found that the electrical parameters are seriously affected, when the absorber thickness is lower than 600 nm, mainly due to recombination at CZTS/Molybdenum interface that causes the short-circuit current density loss of 3.6 mA/cm2. An additional source of recombination, inside the absorber layer, affects the short-circuit current density and produces a loss of about 2.1 mA/cm2 above this range of absorber thickness. The characteristic shows that the performance of the device is also limited by a double diode behavior. This effect is reduced when the absorber layer is skinny. Our investigations showed that, for solar cells having a CZTS absorber layer of thin thickness and high-quality materials (defects density ~1015 cm−3), doping less than 1016 cm−3 is especially beneficial. Such CZTS based solar cell devices could lead to conversion efficiencies higher than 15% and to improvement of about 100 mV on the open-circuit voltage value. Our results are in conformity with experimental reports existing in the literature. M. Djinkwi Wanda, S. Ouédraogo, F. Tchoffo, F. Zougmoré, and J. M. B. Ndjaka Copyright © 2016 M. Djinkwi Wanda et al. All rights reserved. Adsorption and Photocatalytic Kinetics of Visible-Light Response N-Doped TiO2 Nanocatalyst for Indoor Acetaldehyde Removal under Dark and Light Conditions Thu, 28 Apr 2016 13:29:50 +0000 http://www.hindawi.com/journals/ijp/2016/3058429/ Understanding the removal nature of the indoor volatile organic compounds under realistic environment conditions would give clear guidance for the development of air purification devices. The study investigated the removal of indoor acetaldehyde using visible-light-responsive N-doped TiO2 (N-TiO2) photocatalyst under visible-light irradiation (light) and in the absence of light (dark). The adsorption kinetics of acetaldehyde onto N-TiO2 followed a pseudo-second-order model. The magnitude of acetaldehyde adsorption is proportional to temperature, and the results were fitted to the Langmuir isotherm model. Moreover, the effect of initial acetaldehyde concentration and visible-light intensity on the photooxidation of acetaldehyde was well described by the Langmuir-Hinshelwood model. Results show that the mesoporous N-TiO2 catalyst had a high ability to absorb acetaldehyde in the dark condition, and then acetaldehyde was subsequently photooxidized under visible-light irradiation. The adsorption capacity was found to increase with decreasing temperature. The negative value of ° and the positive value of ° indicate that the adsorption of acetaldehyde onto N-TiO2 was a spontaneous process. Finally, a reaction scheme for removal process of indoor acetaldehyde by N-TiO2 was proposed. Yu-Hao Lin, Chih-Huang Weng, Jing-Hua Tzeng, and Yao-Tung Lin Copyright © 2016 Yu-Hao Lin et al. All rights reserved. Laboratory and Pilot-Plant Scale Photocatalytic Degradation of Polychlorinated Biphenyls in Seawater Using CM-n-TiO2 Nanoparticles Thu, 28 Apr 2016 12:07:21 +0000 http://www.hindawi.com/journals/ijp/2016/8471960/ Photocatalytic degradation of polychlorinated biphenyls (PCBs) in seawater was successfully achieved at laboratory level with UV light and at pilot-plant scale under natural solar radiation using carbon-modified titanium oxide (CM-n-TiO2) nanoparticles. The photocatalytic performance of CM-n-TiO2 was comparatively evaluated with reference n-TiO2 under identical conditions. As a result of carbon incorporation, significant enhancement of photodegradation efficiency using CM-n-TiO2 was clearly observed. To optimize the operating parameters, the effects of catalyst loading and pH of the solution on the photodegradation rate of PCBs were investigated. The best degradation rate was obtained at pH 5 and CM-n-TiO2 loading of 0.5 g L−1. The photodegradation results fitted the Langmuir-Hinshelwood model and obeyed pseudo-first-order reaction kinetics. Yasser A. Shaban, Mohamed A. El Sayed, Amr A. El Maradny, Radwan Kh. Al Farawati, Mosa I. Al Zobidi, and Shahed U. M. Khan Copyright © 2016 Yasser A. Shaban et al. All rights reserved. Growth Parameters for Films of Hydrothermally Synthesized One-Dimensional Nanocrystals of Zinc Oxide Tue, 26 Apr 2016 12:01:43 +0000 http://www.hindawi.com/journals/ijp/2016/3153170/ Zinc oxide has been the focus of material research due to its potential applications in a variety of novel fields. The material exhibits anisotropic growth in the form of single crystal rods/wires of length in microns and thickness in several tens of nanometers through a facile and low temperature hydrothermal route wherein size, morphology, orientation, and growth rate are strongly dependent on a number of synthesis parameters. In this review article we intend to present/discuss the effects of important growth parameters of zinc oxide that have been reported in the literature. These parameters include concentration of the precursor solution, growth time, role of hexamine, synthesis temperature, pH of the precursor, and seeding layer deposited on a substrate. Mohammad A. Mahmood, Sadaqat Jan, Ibrar A. Shah, and Imran Khan Copyright © 2016 Mohammad A. Mahmood et al. All rights reserved. New Surface Aspects towards Photocatalytic Activity of Doped Supported Titanium Dioxide Wed, 20 Apr 2016 14:17:09 +0000 http://www.hindawi.com/journals/ijp/2016/1035402/ The present work aims to synthesize nanoscale well dispersed TiO2/SiO2 and TiO2/Al2O3 nanoparticle photocatalysts via an impregnation method for the removal of methyl orange, which was used as a model compound of organic pollutant in wastewater, from an aqueous medium. Also within this frame work, La and Ce metals were loaded onto the surfaces of TiO2/SiO2 and TiO2/Al2O3 by an impregnation method to enhance the photocatalytic activity of the nanoparticles; the activities and physicochemical properties of the photocatalysts were compared before and after loading of metallic La and Ce. The oxide system was characterized by different techniques, including XRD, UV-Vis spectroscopy, FT-IR spectroscopy, SEM, and EDX spectroscopy. Finally, the optimal conditions to complete the photocatalytic oxidation of methyl orange dye were studied. This work holds promise for the efficient photodegradation of pollutants by nanoparticle photocatalysts. Samia A. Kosa, Eman Z. Hegazy, Saleha S. Maashi, Islam H. Abd El Maksod, and Laila M. Al-Harbi Copyright © 2016 Samia A. Kosa et al. All rights reserved. Effective Carbon Dioxide Photoreduction over Metals (Fe-, Co-, Ni-, and Cu-) Incorporated TiO2/Basalt Fiber Films Sun, 17 Apr 2016 09:25:33 +0000 http://www.hindawi.com/journals/ijp/2016/5195138/ Mineralogical basalt fibers as a complementary adsorbent were introduced to improve the adsorption of CO2 over the surfaces of photocatalysts. TiO2 photocatalysts (M-TiO2) incorporated with 5.0 mol.% 3d-transition metals (Fe, Co, Ni, and Cu) were prepared using a solvothermal method and mixed with basalt fibers for applications to CO2 photoreduction. The resulting 5.0 mol.% M-TiO2 powders were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectroscopy, photoluminescence, Brunauer, Emmett, and Teller surface area, and CO2-temperature-programmed desorption. A paste composed of two materials was coated and fixed on a Pyrex plate by a thermal treatment. The 5.0 mol.% M-TiO2/basalt fiber films increased the adsorption of CO2 significantly, indicating superior photocatalytic behavior compared to pure TiO2 and basalt fiber films, and produced 158~360 μmol  L−1 CH4 gases after an 8 h reaction. In particular, the best performance was observed over the 5.0 mol.% Co-TiO2/basalt fiber film. These results were attributed to the effective CO2 gas adsorption and inhibition of photogenerated electron-hole pair recombination. Jeong Yeon Do, Byeong Sub Kwak, Sun-Min Park, and Misook Kang Copyright © 2016 Jeong Yeon Do et al. All rights reserved. Investigating Theoretical PV Energy Generation Patterns with Their Relation to the Power Load Curve in Poland Thu, 14 Apr 2016 09:39:11 +0000 http://www.hindawi.com/journals/ijp/2016/3789840/ Polish energy sector is (almost from its origin) dominated by fossil fuel feed power. This situation results from an abundance of relatively cheap coal (hard and lignite). Brown coal due to its nature is the cheapest energy source in Poland. However, hard coal which fuels 60% of polish power plants is picking up on prices and is susceptible to the coal imported from neighboring countries. Forced by the European Union (EU) regulations, Poland is struggling at achieving its goal of reaching 15% of energy consumption from renewable energy sources (RES) by 2020. Over the year 2015, RES covered 11.3% of gross energy consumption but this generation was dominated by solid biomass (over 80%). The aim of this paper was to answer the following research questions: What is the relation of irradiation values to the power load on a yearly and daily basis? and how should photovoltaics (PV) be integrated in the polish power system? Conducted analysis allowed us to state that there exists a negative correlation between power demand and irradiation values on a yearly basis, but this is likely to change in the future. Secondly, on average, daily values of irradiation tend to follow power load curve over the first hours of the day. Jakub Jurasz and Jerzy Mikulik Copyright © 2016 Jakub Jurasz and Jerzy Mikulik. All rights reserved. The Detailed Evolution of Carbon Spheres by Hydrothermal Method Tue, 12 Apr 2016 16:14:23 +0000 http://www.hindawi.com/journals/ijp/2016/9057418/ Carbon spheres (CSs) can be synthesized easily by hydrothermal method using various solutions and a lot of mechanisms have been employed to explain their formation. In our work, some special phenomena such as the uniform size and surface corruption have been found as the reaction time increased. However, less attention has been focused on the detailed evolution phenomena of CSs. In order to understand these special phenomena well, classical nucleation theory was employed to study the reaction dynamics of CSs during the evolution processes. This work not only deeply reveals the evolution mechanism of CSs, but also opens a possible way for the control of size and morphologies of CSs through hydrothermal methods. Trevor Mwenya, Huiyang Fan, Han Dai, and Meicheng Li Copyright © 2016 Trevor Mwenya et al. All rights reserved. Solar PV/Thermal Research Thu, 07 Apr 2016 08:10:09 +0000 http://www.hindawi.com/journals/ijp/2016/2396973/ Xudong Zhao, Clito Afonso, and Jie Ji Copyright © 2016 Xudong Zhao et al. All rights reserved. Modeling of Drift Effects on Solar Tower Concentrated Flux Distributions Sun, 03 Apr 2016 08:54:53 +0000 http://www.hindawi.com/journals/ijp/2016/8375361/ A novel modeling tool for calculation of central receiver concentrated flux distributions is presented, which takes into account drift effects. This tool is based on a drift model that includes different geometrical error sources in a rigorous manner and on a simple analytic approximation for the individual flux distribution of a heliostat. The model is applied to a group of heliostats of a real field to obtain the resulting flux distribution and its variation along the day. The distributions differ strongly from those obtained assuming the ideal case without drift or a case with a Gaussian tracking error function. The time evolution of peak flux is also calculated to demonstrate the capabilities of the model. The evolution of this parameter also shows strong differences in comparison to the case without drift. Luis O. Lara-Cerecedo, Isaias Moreno-Cruz, Nun Pitalúa-Diaz, and Camilo A. Arancibia-Bulnes Copyright © 2016 Luis O. Lara-Cerecedo et al. All rights reserved. Simulation on the Performance of Dye Solar Cell Incorporated with TiO2 Passivation Layer Tue, 29 Mar 2016 12:29:44 +0000 http://www.hindawi.com/journals/ijp/2016/8507625/ Dye Solar Cell (DSC) has started to gain interest in the recent years for practical application because of its ecofriendly, low cost, and easy fabrication. However, its efficiency is still not as competitive as the conventional silicon based solar cell. One of the research efforts to improve the efficiency of DSC is to use the passivation layer in between the photoelectrode material and the conductive oxide substrate. Thus, the objective of this simulation study is to investigate the effect of passivation layer on the performance of DSC. Properties from literatures which are based on physical work were captured as the input for the simulation using process, ATHENA, and device, ATLAS, simulator. Results have shown that the addition of two-20 nm TiO2 passivation layers on DSC can enhance the efficiency by 11% as the result of less recombination, higher electron mobility, and longer electron lifetime. Unan Yusmaniar Oktiawati, Norani Muti Mohamed, and Zainal Arif Burhanudin Copyright © 2016 Unan Yusmaniar Oktiawati et al. All rights reserved. Design and Performance Evaluation of a Solar Assisted Heat Pump Dryer Integrated with Biomass Furnace for Red Chilli Thu, 24 Mar 2016 11:43:39 +0000 http://www.hindawi.com/journals/ijp/2016/8763947/ The performance of a solar assisted heat pump dryer integrated with biomass furnace has been designed and evaluated for drying red chillies, and drying kinetics of red chillies were evaluated. The red chillies were dried from 22 kg with moisture content of 4.26 db to moisture content of 0.08 db which needed 11 hours, with the average drying chamber temperature, drying chamber relative humidity, and an air mass flow rate of 70.5°C, 10.1%, and 0.124 kg/s, respectively, while the open sun drying needed 62 hours. Compared to open sun drying, this dryer yielded 82% saving in drying time. The drying rate, the specific moisture extraction rate, and thermal efficiency of the dryer were estimated in average to be about 1.57 kg/h, 0.14 kg/kWh, and 9.03%, respectively. Three mathematical models, the Newton, Henderson-Pabis, and Page models, were fitted to the experimental data on red chillies dried by solar assisted heat pump dryer integrated with biomass furnace and open sun drying. The performance of these models was evaluated by comparing the coefficient of determination (), mean bias error (MBE), and root mean-square error (RMSE). The Page model gave the best results for representing drying kinetics of red chillies. M. Yahya Copyright © 2016 M. Yahya. All rights reserved. Influence of Crucible Thermal Conductivity on Crystal Growth in an Industrial Directional Solidification Process for Silicon Ingots Sun, 20 Mar 2016 09:33:16 +0000 http://www.hindawi.com/journals/ijp/2016/8032709/ We carried out transient global simulations of heating, melting, growing, annealing, and cooling stages for an industrial directional solidification (DS) process for silicon ingots. The crucible thermal conductivity is varied in a reasonable range to investigate its influence on the global heat transfer and silicon crystal growth. It is found that the crucible plays an important role in heat transfer, and therefore its thermal conductivity can influence the crystal growth significantly in the entire DS process. Increasing the crucible thermal conductivity can shorten the time for melting of silicon feedstock and growing of silicon crystal significantly, and therefore large thermal conductivity is helpful in saving both production time and power energy. However, the high temperature gradient in the silicon ingots and the locally concave melt-crystal interface shape for large crucible thermal conductivity indicate that high thermal stress and dislocation propagation are likely to occur during both growing and annealing stages. Based on the numerical simulations, some discussions on designing and choosing the crucible thermal conductivity are presented. Zaoyang Li, Lijun Liu, Yunfeng Zhang, and Genshu Zhou Copyright © 2016 Zaoyang Li et al. All rights reserved. Ag/AgCl Loaded Bi2WO6 Composite: A Plasmonic Z-Scheme Visible Light-Responsive Photocatalyst Thu, 17 Mar 2016 12:42:08 +0000 http://www.hindawi.com/journals/ijp/2016/4054351/ Hierarchical flower-like Bi2WO6 was successfully synthesized by facile hydrothermal method at low pH. And Ag/AgCl was loaded by photoreduction on its surface. As-prepared photocatalysts were characterized by various techniques. Bi2WO6 was successfully synthesized at a size of 2-3 μm. Depositing Ag/AgCl did not destroy the crystal structure, and both Ag+ and metallic Ag0 were found. The band gap of the composite was 2.57 eV, which indicates that visible light could be the activating irradiation. In the photocatalytic activity test, the composite with 10 wt% Ag/AgCl boasted the highest removal efficiency (almost 100%) in 45 min. The significant enhancement can be attributed to the surface plasmon resonance (SPR) effect and the establishment of heterostructures between Ag/AgCl and Bi2WO6. A possible mechanism of photocatalytic oxidation in the presence of Ag/AgCl-Bi2WO6 was proposed. This work sheds light on the potential applications of plasmonic metals in photocatalysis to enhance their activities. Xiangchao Meng and Zisheng Zhang Copyright © 2016 Xiangchao Meng and Zisheng Zhang. All rights reserved. A New Approach for Studying Bond Rupture/Closure of a Spiro Benzopyran Photochromic Material: Reactivity Descriptors Derived from Frontier Orbitals and DFT Computed Electrostatic Potential Energy Surface Maps Tue, 15 Mar 2016 13:34:09 +0000 http://www.hindawi.com/journals/ijp/2016/6765805/ This paper focuses on computations technique within the framework of the TD-DFT theory for studying the relationship between structure-properties of reversible conversion of photochromic materials. Specifically, we report on 1′,3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole] (SP) and its isomers. TD-DFT calculated UV-Vis electronic spectra of the closed and open isomers of this photochromic material are in excellent agreement with the experimental results. Moreover, this paper reports on the results of theoretical investigations of reactivity indices that may govern the conversion between spiropyrans and its isomers. In addition, the solvent and rigidity of the medium significantly control the thermal bleaching of the photogenerated colored isomers and hence the switch ability pattern of the photochromic material. The effect of molecular structure computed by DFT in gas-phase and solvents on bond length has been shown to correlate with photochromic properties. For this compound, DFT optimized geometry could be used to predict photochromism. Furthermore, in an attempt to predict the driving force for MC → SP, this work explores, for the first time, profitable exploitation of the calculated and visualized mapped electrostatic potential energy surfaces (ESP map). Interestingly, it seems that the electrostatic potential forces over the molecular fragments govern spirobond rupture/closure reactions. Thermodynamically, all-trans-colored isomer (CTT) is the most stable merocyanine-like form. M. S. A. Abdel-Mottaleb and Sarah N. Ali Copyright © 2016 M. S. A. Abdel-Mottaleb and Sarah N. Ali. All rights reserved. An Efficient Metal-Free Hydrophilic Carbon as a Counter Electrode for Dye-Sensitized Solar Cells Tue, 15 Mar 2016 12:34:29 +0000 http://www.hindawi.com/journals/ijp/2016/5186762/ This study presents a new cost-effective metal-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). CE was prepared by doctor blading a hydrophilic carbon (HC) particle on a fluorine-doped tin oxide substrate. Thereafter, HC CE was characterized using X-ray diffraction, profilometry, four-point probe testing, and cyclic voltammetry. A 2 µm thick HC CE revealed a comparable catalytic activity to that of the Pt electrode under the same experimental conditions. DSSC based on HC CE was analyzed and showed of 6.87 mA/cm2 close to that of DSSC with Pt CE (7.0 mA/cm2). More importantly, DSSC based on HC CE yielded a power conversion efficiency () of 2.93% under AM 1.5 irradiation (100 mW/cm2), which was comparable to that of DSSC based on standard Pt CE. These findings suggest that HC CE could be a promising CE for low-cost DSSCs. Mojgan Kouhnavard, Norasikin Ahmad Ludin, Babak Vazifehkhah Ghaffari, Kamaruzzaman Sopian, Norshazlinah Abdul Karim, and Mikio Miyake Copyright © 2016 Mojgan Kouhnavard et al. All rights reserved. Indium-Free PTB7/PC71BM Polymer Solar Cells with Solution-Processed Al:ZnO Electrodes on PET Substrates Tue, 15 Mar 2016 09:40:36 +0000 http://www.hindawi.com/journals/ijp/2016/2047591/ Inverted PTB7/PC71BM polymer solar cells are prepared on solution-processed Al:ZnO transparent contacts on PET substrates. Al:ZnO is deposited by a low temperature chemical bath deposition route (T < 100°C at any step) to comply with the temperature sensitive substrate. A maximum conversion efficiency of 6.4% and 6.9% is achieved for the indium-free solar cells on PET and glass substrates, respectively. The devices are relatively stable in air whereby an initial efficiency loss in the order of 15% after storage for 15 days can be fully recovered by light soaking. P. Fuchs, A. Paracchino, H. Hagendorfer, L. Kranz, T. Geiger, Y. E. Romanyuk, A. N. Tiwari, and F. Nüesch Copyright © 2016 P. Fuchs et al. All rights reserved. A Power Case Study for Monocrystalline and Polycrystalline Solar Panels in Bursa City, Turkey Mon, 14 Mar 2016 13:16:17 +0000 http://www.hindawi.com/journals/ijp/2016/7324138/ It was intended to reveal the time dependent power generation under different loads for two different solar panels under the conditions of Bursa province in between August 19 and 25, 2014. The testing sets include solar panels, inverter, multimeter, accumulator, regulator, pyranometer, pyrheliometer, temperature sensor, and datalogger. The efficiency of monocrystalline and polycrystalline solar panels was calculated depending on the climatic data’s measurements. As the result of the study, the average performances of monocrystalline and polycrystalline panels are 42.06 and 39.80 Wh, respectively. It was seen that 87.14 W instantaneous power could be obtained from monocrystalline solar panel and that 80.17 W instantaneous power could be obtained from polycrystalline solar panel under maximum total radiation (1001.13 W/m2). Within this frame, it was determined that monocrystalline solar panel is able to operate more efficiently under the conditions of Bursa compared to polycrystalline solar panel. When the multivariate correlations coefficients were examined statistically, a significant relationship in positive direction was detected between total and direct radiation and ambient temperature on energy generation from monocrystalline and polycrystalline panel. Ayşegül Taşçıoğlu, Onur Taşkın, and Ali Vardar Copyright © 2016 Ayşegül Taşçıoğlu et al. All rights reserved. Temperature Dependent Electrical Transport in Al/Poly(4-vinyl phenol)/p-GaAs Metal-Oxide-Semiconductor by Sol-Gel Spin Coating Method Thu, 10 Mar 2016 15:39:21 +0000 http://www.hindawi.com/journals/ijp/2016/6157905/ Deposition of poly(4-vinyl phenol) insulator layer is carried out by applying the spin coating technique onto p-type GaAs substrate so as to create Al/poly(4-vinyl phenol)/p-GaAs metal-oxide-semiconductor (MOS) structure. Temperature was set to 80–320 K while the current-voltage (I-V) characteristics of the structure were examined in the study. Ideality factor (n) and barrier height () values found in the experiment ranged from 3.13 and 0.616 eV (320 K) to 11.56 and 0.147 eV (80 K). Comparing the thermionic field emission theory and thermionic emission theory, the temperature dependent ideality factor behavior displayed that thermionic field emission theory is more valid than the latter. The calculated tunneling energy was 96 meV. Şadan Özden, Cem Tozlu, and Osman Pakma Copyright © 2016 Şadan Özden et al. All rights reserved. Flexible Bench-Scale Recirculating Flow CPC Photoreactor for Solar Photocatalytic Degradation of Methylene Blue Using Removable TiO2 Immobilized on PET Sheets Thu, 10 Mar 2016 08:29:35 +0000 http://www.hindawi.com/journals/ijp/2016/9270492/ TiO2 immobilized on polyethylene (PET) nonwoven sheet was used in the solar photocatalytic degradation of methylene blue (MB). TiO2 Evonik Aeroxide P25 was used in this study. The amount of loaded TiO2 on PET was approximately 24%. Immobilization of TiO2 on PET was conducted by dip coating process followed by exposing to mild heat and pressure. TiO2/PET sheets were wrapped on removable Teflon rods inside home-made bench-scale recirculating flow Compound Parabolic Concentrator (CPC) photoreactor prototype (platform 0.7 × 0.2 × 0.4 m3). CPC photoreactor is made up of seven low iron borosilicate glass tubes connected in series. CPC reflectors are made of stainless steel 304. The prototype was mounted on a platform tilted at 30°N local latitude in Cairo. A centrifugal pump was used to circulate water containing methylene blue (MB) dye inside the glass tubes. Efficient photocatalytic degradation of MB using TiO2/PET was achieved upon the exposure to direct sunlight. Chemical oxygen demand (COD) analyses reveal the complete mineralization of MB. Durability of TiO2/PET composite was also tested under sunlight irradiation. Results indicate only 6% reduction in the amount of TiO2 after seven cycles. No significant change was observed for the physicochemical characteristics of TiO2/PET after the successive irradiation processes. Doaa M. EL-Mekkawi, Norhan Nady, Nourelhoda A. Abdelwahab, Walied A. A. Mohamed, and M. S. A. Abdel-Mottaleb Copyright © 2016 Doaa M. EL-Mekkawi et al. All rights reserved. Noble Metal Decoration and Presulfation on TiO2: Increased Photocatalytic Activity and Efficient Esterification of n-Butanol with Citric Acid Wed, 02 Mar 2016 11:30:21 +0000 http://www.hindawi.com/journals/ijp/2016/4618924/ TiO2 has been widely used as a key catalyst in photocatalytic reactions; it also shows good catalytic activity for esterification reactions. Different sulfated M-TiO2 nanoparticles (M = Ag, Au, Rh, and Pt) were prepared by photodeposition and ultrasonic methods. The results show that the noble metal nanoparticles, which were loaded onto a TiO2 surface, slightly affected the crystal phase and particle size of TiO2. Among all the catalysts, /Au-TiO2 exhibited the best catalytic activity in the esterification reaction for the synthesis of citric acid n-butyl acetate and in the decomposition of methyl orange, as confirmed by a high conversion rate of up to 98.2% and 100% degradation rate, respectively. This can be attributed to an increase in the Lewis acidity of the catalyst and increased separation efficiency of electron-hole pairs. This superior catalyst has great potential applications in esterification reactions and wastewater treatments. Yu Niu, Pan Huang, Fuying Li, Kai Yang, Jinbei Yang, Renzhang Wang, Cheng Lin, and Ting Qiu Copyright © 2016 Yu Niu et al. All rights reserved. Synthesis of CdS Sensitized TiO2 Photocatalysts: Methylene Blue Adsorption and Enhanced Photocatalytic Activities Mon, 29 Feb 2016 06:42:13 +0000 http://www.hindawi.com/journals/ijp/2016/2947510/ A series of CdS/ nanocomposites with different Cd to Ti molar ratio were synthesized from P25- nanopowder using microwave-assisted hydrothermal method. The as-produced powders were characterized by XRD, electron microscopy, EDX, and UV-Vis diffuse reflectance spectroscopy. The adsorption capacity and photocatalytic activity of the samples were investigated using methylene blue as a model pollutant. Sorption tests revealed that the adsorption of MB onto the samples obeys the Freundlich-Langmuir isotherm model. The sorption capacity decreased as follows: . The results of the photocatalytic tests under high-intensity discharge (HID) lamp revealed that CdS/ powders with low Cd to Ti molar ratios exhibited much higher activities than P25-. The CdS/ sample with 20% CdS/(TCd2) showed the most activity among all these samples. The results also show that the Cd to Ti molar ratio of the nanocomposite has a significant effect on the photodegradation of MB and the enhanced activities exhibited by the nanocomposites are because of the low rate of electron-hole recombination. A. B. Makama, A. Salmiaton, E. B. Saion, T. S. Y. Choong, and N. Abdullah Copyright © 2016 A. B. Makama et al. All rights reserved. Efficacy of 670 nm Light Therapy to Protect against Photoreceptor Cell Death Is Dependent on the Severity of Damage Sun, 28 Feb 2016 09:54:08 +0000 http://www.hindawi.com/journals/ijp/2016/2734139/ Photobiomodulation at a wavelength of 670 nm has been shown to be effective in preventing photoreceptor cell death in the retina. We treated Sprague-Dawley (SD) rats with varying doses of 670 nm light (9; 18; 36; 90 J/cm2) before exposing them to different intensities of damaging white light (750; 1000; 1500 lux). 670 nm light exhibited a biphasic response in its amelioration of cell death in light-induced degeneration in vivo. Lower light damage intensities required lower doses of 670 nm light to reduce TUNEL cell death. At higher damage intensities, the highest dose of 670 nm light showed protection. In vitro, the Seahorse XFe96 Extracellular Flux Analyzer revealed that 670 nm light directly influences mitochondrial metabolism by increasing the spare respiratory capacity of mitochondria in 661 W photoreceptor-like cells in light damaged conditions. Our findings further support the use of 670 nm light as an effective treatment against retinal degeneration as well as shedding light on the mechanism of protection through the increase of the mitochondrial spare respiratory capacity. Joshua A. Chu-Tan, Matt Rutar, Kartik Saxena, Yunlu Wu, Lauren Howitt, Krisztina Valter, Jan Provis, and Riccardo Natoli Copyright © 2016 Joshua A. Chu-Tan et al. All rights reserved. Triple Layer Antireflection Design Concept for the Front Side of c-Si Heterojunction Solar Cell Based on the Antireflective Effect of nc-3C-SiC:H Emitter Layer Thu, 25 Feb 2016 13:55:50 +0000 http://www.hindawi.com/journals/ijp/2016/5282851/ We investigated the antireflective (AR) effect of hydrogenated nanocrystalline cubic silicon carbide (nc-3C-SiC:H) emitter and its application in the triple layer AR design for the front side of silicon heterojunction (SHJ) solar cell. We found that the nc-3C-SiC:H emitter can serve both as an emitter and antireflective coating for SHJ solar cell, which enables us to realize the triple AR design by adding one additional dielectric layer to normally used SHJ structure with a transparent conductive oxide (TCO) and an emitter layer. The optimized SHJ structure with the triple layer AR coating (LiF/ITO/nc-3C-SiC:H) exhibit a short circuit current density () of 38.65 mA/cm2 and lower reflectivity of about 3.42% at wavelength range of 300 nm–1000 nm. Erick Omondi Ateto, Makoto Konagai, and Shinsuke Miyajima Copyright © 2016 Erick Omondi Ateto et al. All rights reserved. The Effect of Photovoltaic Panels on the Rooftop Temperature in the EnergyPlus Simulation Environment Thu, 25 Feb 2016 10:16:07 +0000 http://www.hindawi.com/journals/ijp/2016/9020567/ In this paper, the effects that photovoltaic (PV) panels have on the rooftop temperature in the EnergyPlus simulation environment were investigated for the following cases: with and without PV panels, with and without exposure to sunlight, and using roof materials with different thermal conductivities and for different climatic zones. The results demonstrate that heat transfer by convection, radiation, and conduction in the air gaps between PV panels and the building envelope can be simulated in the EnergyPlus environment when these air gaps are in the “air conditioning zone.” Nevertheless, in most cases, particularly on the rooftop, the air gaps between the PV panels and the building envelope cannot be set as the “air conditioning zone.” Therefore, in this case, none of the EnergyPlus models are appropriate to simulate the effect that PV panels have on the rooftop temperature. However, all the terms of the Heat Balance Model, including the absorbed direct and diffuse solar radiation, net long-wave radiation with the air and surroundings, convective exchange with the outside air, and conduction flux in or out of the surface, can still be used to calculate the temperature and heat flux within the BIPV’s air gap. Changhai Peng and Jianqiang Yang Copyright © 2016 Changhai Peng and Jianqiang Yang. All rights reserved.