International Journal of Photoenergy http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Influence of Substrate on Crystal Orientation of Large-Grained Si Thin Films Formed by Metal-Induced Crystallization Thu, 23 Apr 2015 14:20:57 +0000 http://www.hindawi.com/journals/ijp/2015/790242/ Producing large-grained polycrystalline Si (poly-Si) film on glass substrates coated with conducting layers is essential for fabricating Si thin-film solar cells with high efficiency and low cost. We investigated how the choice of conducting underlayer affected the poly-Si layer formed on it by low-temperature (500°C) Al-induced crystallization (AIC). The crystal orientation of the resulting poly-Si layer strongly depended on the underlayer material: (100) was preferred for Al-doped-ZnO (AZO) and indium-tin-oxide (ITO); (111) was preferred for TiN. This result suggests Si heterogeneously nucleated on the underlayer. The average grain size of the poly-Si layer reached nearly 20 µm for the AZO and ITO samples and no less than 60 µm for the TiN sample. Thus, properly electing the underlayer material is essential in AIC and allows large-grained Si films to be formed at low temperatures with a set crystal orientation. These highly oriented Si layers with large grains appear promising for use as seed layers for Si light-absorption layers as well as for advanced functional materials. Kaoru Toko, Mitsuki Nakata, Atsushi Okada, Masato Sasase, Noritaka Usami, and Takashi Suemasu Copyright © 2015 Kaoru Toko et al. All rights reserved. Heterovalent Cation Substitutional and Interstitial Doping in Semiconductor Sensitizers for Quantum Dot Cosensitized Solar Cell Thu, 23 Apr 2015 07:53:19 +0000 http://www.hindawi.com/journals/ijp/2015/326850/ Doped films of TiO2/PbS/CdS have been prepared by successive ionic layer adsorption and reaction (SILAR) method. Bi- and Ag-doped-PbS quantum dot (QD) were produced by admixing Bi3+ or Ag+ during deposition and the existing forms of the doping element in PbS QD were analyzed. The results show that Bi3+ entered the cube space of PbS as donor yielding interstitial doping Bi-doped-PbS QD, while Ag+ replaced Pb2+ of PbS as acceptor yielding substitutional doping Ag-doped-PbS QD. The novel Bi-doped-PbS/CdS and Ag-doped-PbS/CdS quantum dot cosensitized solar cell (QDCSC) were fabricated and power conversion efficiency (PCE) of 2.4% and 2.2% was achieved, respectively, under full sun illumination. Ningning Zhang, Xiaoping Zou, and Yanyan Gao Copyright © 2015 Ningning Zhang et al. All rights reserved. Homogenized Poly(3-hexylthiophene)/Methanofullerene Film by Addition of End-Functionalized Compatibilizer and Its Application to Polymer Solar Cells Thu, 23 Apr 2015 06:53:31 +0000 http://www.hindawi.com/journals/ijp/2015/762532/ A uniformed poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blended film prepared by using spin-coating process is achieved by addition of 10% hydroxyl group end-functionalized P3HT (HOC-P3HT-COH) as a compatibilizer. Ratio of P3HT/PCBM on a spin-coated film has been improved from 1 : 1.22 on the edge and 1 : 0.85 in the center of substrate (substrate size, 2 cm × 3 cm) to 1 : 1.03 on the edge and 1 : 0.94 in the center for P3HT/HOC-P3HT-COH/PCBM film (1 : 0.1 : 1). Homogeneous and reproducible polymer solar cell with an average of 3.71% power conversion efficiency under AM1.5G irradiation is fabricated with 10% HOC-P3HT-COH in P3HT/PCBM layer. Ping-Tsung Huang, Yi-Hao Chen, Bo-Yu Lin, and Wei-Ping Chuang Copyright © 2015 Ping-Tsung Huang et al. All rights reserved. Influence of Surface Morphology on the Effective Lifetime and Performance of Silicon Heterojunction Solar Cell Thu, 23 Apr 2015 06:48:49 +0000 http://www.hindawi.com/journals/ijp/2015/273615/ Different etching times are used to etch silicon wafers. Effects of surface morphology on wafer minority carrier lifetime, passivation quality, and heterojunction solar cell (HJ) performance are investigated. The numbers of mountains and valleys, defined as turning points, on wafer surfaces are used to explain the minority carrier lifetime variations. For a wafer with a smaller amount of turning points, hydrogenated amorphous silicon (a-Si:H) passivation quality can be comparable to ideal iodine-ethanol solution passivation. If the wafer has a notable amount of turning points, the carrier lifetime decreases as the a-Si:H layer will not be able to be well-deposited on turning points. Furthermore, the PC1D simulation indicates that an optimal device conversion efficiency of 21.94% can be achieved at an etching time of 60 min, where a best combination of short-circuit current and open-circuit voltage is obtained. Shui-Yang Lien, Yun-Shao Cho, Yan Shao, Chia-Hsun Hsu, Chia-Chi Tsou, Wei Yan, Pin Han, and Dong-Sing Wuu Copyright © 2015 Shui-Yang Lien et al. All rights reserved. Optimization of Solar Module Encapsulant Lamination by Optical Constant Determination of Ethylene-Vinyl Acetate Thu, 23 Apr 2015 06:38:30 +0000 http://www.hindawi.com/journals/ijp/2015/276404/ This investigation elucidates the physical properties of ethylene-vinyl acetate (EVA) used in the lamination process of module encapsulation and the module performance from the optical transmission to the photoelectric power. In module encapsulation, the effects of the lamination parameters on the module performance, transmittance, and stack adhesion have been considered as they were found to influence the reliability of the module. The determination of the optical constants of EVA may serve as a nondestructive analytical method for optimizing the module encapsulation, on the basis of its effects on the optical transmittance, gel content, peel strength, and performance power. Bing-Mau Chen, Cheng-Yu Peng, Ju-Lu Cho, and Glen Andrew Porter Copyright © 2015 Bing-Mau Chen et al. All rights reserved. Development and Prospect of Nanoarchitectured Solar Cells Thu, 23 Apr 2015 06:24:58 +0000 http://www.hindawi.com/journals/ijp/2015/382389/ This paper gives an overview of the development and prospect of nanotechnologies utilized in the solar cell applications. Even though it is not clearly pointed out, nanostructures indeed have been used in the fabrication of conventional solar cells for a long time. However, in those circumstances, only very limited benefits of nanostructures have been used to improve cell performance. During the last decade, the development of the photovoltaic device theory and nanofabrication technology enables studies of more complex nanostructured solar cells with higher conversion efficiency and lower production cost. The fundamental principles and important features of these advanced solar cell designs are systematically reviewed and summarized in this paper, with a focus on the function and role of nanostructures and the key factors affecting device performance. Among various nanostructures, special attention is given to those relying on quantum effect. Bo Zhang, Wenxu Xie, and Yong Xiang Copyright © 2015 Bo Zhang et al. All rights reserved. Synthesis, Analysis, and Testing of BiOBr-Bi2WO6 Photocatalytic Heterojunction Semiconductors Mon, 20 Apr 2015 14:26:44 +0000 http://www.hindawi.com/journals/ijp/2015/630476/ In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6 photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6 composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation of Rhodamine B (RhB) under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity. Xiangchao Meng and Zisheng Zhang Copyright © 2015 Xiangchao Meng and Zisheng Zhang. All rights reserved. Design of Incremental Conductance Sliding Mode MPPT Control Applied by Integrated Photovoltaic and Proton Exchange Membrane Fuel Cell System under Various Operating Conditions for BLDC Motor Sun, 19 Apr 2015 17:04:12 +0000 http://www.hindawi.com/journals/ijp/2015/828129/ This paper proposes an integrated photovoltaic (PV) and proton exchange membrane fuel cell (PEMFC) system for continuous energy harvesting under various operating conditions for use with a brushless DC motor. The proposed scheme is based on the incremental conductance (IncCond) algorithm combined with the sliding mode technique. Under changing atmospheric conditions, the energy conversion efficiency of a PV array is very low, leading to significant power losses. Consequently, increasing efficiency by means of maximum power point tracking (MPPT) is particularly important. To manage such a hybrid system, control strategies need to be established to achieve the aim of the distributed system. Firstly, a Matlab/Simulink based model of the PV and PEMFC is developed and validated, as well as the incremental conductance sliding (ICS) MPPT technique; then, different MPPT algorithms are employed to control the PV array under nonuniform temperature and insolation conditions, to study these algorithms effectiveness under various operating conditions. Conventional techniques are easy to implement but produce oscillations at MPP. Compared to these techniques, the proposed technique is more efficient; it produces less oscillation at MPP in the steady state and provides more precise tracking. Jehun Hahm, Hyoseok Kang, Jaeho Baek, Heejin Lee, and Mignon Park Copyright © 2015 Jehun Hahm et al. All rights reserved. Technoeconomical Assessment of Optimum Design for Photovoltaic Water Pumping System for Rural Area in Oman Thu, 16 Apr 2015 13:22:16 +0000 http://www.hindawi.com/journals/ijp/2015/514624/ Photovoltaic (PV) systems have been used globally for a long time to supply electricity for water pumping system for irrigation. System cost drops down with time since PV technology, efficiency, and design methodology have been improved and cost of wattage drops dramatically in the last decade. In the present paper optimum PV system design for water pumping system has been proposed for Oman. Intuitive and numerical methods were used to design the system. HOMER software as a numerical method was used to design the system to come up with optimum design for Oman. Also, REPS.OM software has been used to find the optimum design based on hourly meteorological data. The daily solar energy in Sohar was found to be 6.182 kWh/m2·day. However, it is found that the system annual yield factor is 2024.66 kWh/kWp. Furthermore, the capacity factor was found to be 23.05%, which is promising. The cost of energy and system capital cost has been compared with that of diesel generator and systems in literature. The comparison shows that the cost of energy is 0.180, 0.309, and 0.790 USD/kWh for PV-REPS.OM, PV-HOMER, and diesel systems, respectively, which sound that PV water pumping systems are promising in Oman. Hussein A. Kazem, Ali H. A. Al-Waeli, Atma H. K. Al-Kabi, and Asma Al-Mamari Copyright © 2015 Hussein A. Kazem et al. All rights reserved. Sb2S3 Quantum-Dot Sensitized Solar Cells with Silicon Nanowire Photoelectrode Tue, 07 Apr 2015 12:55:55 +0000 http://www.hindawi.com/journals/ijp/2015/213858/ We propose a novel quantum-dot sensitized solar cell (QDSSC) structure that employs a quantum dot/semiconductor silicon (QD/Si) coaxial nanorod array to replace the conventional dye/TiO2/TCO photoelectrode. We replaced the backlight input mode with top-side illumination and used a quantum dot to replace dye as the light-absorbing material. Photon-excited photoelectrons can be effectively transported to each silicon nanorod and conveyed to the counter electrode. We use two-stage metal-assisted etching (MAE) to fabricate the micro-nano hybrid structure on a silicon substrate. We then use the chemical bath deposition (CBD) method to synthesize a Sb2S3 quantum dot on the surface of each silicon nanorod to form the photoelectrode for the quantum dot/semiconductor silicon coaxial nanorod array. We use a xenon lamp to simulate AM 1.5 G (1000 W/m2) sunlight. Then, we investigate the influence of different silicon nanorod arrays and CBD deposition times on the photoelectric conversion efficiency. When an NH (N-type with high resistance) silicon substrate is used, the QD/Si coaxial nanorod array synthesized by three runs of Sb2S3 deposition shows the highest photoelectric conversion efficiency of 0.253%. The corresponding short-circuit current density, open-circuit voltage, and fill factor are 5.19 mA/cm2, 0.24 V, and 20.33%, respectively. You-Da Hsieh, Ming-Way Lee, and Gou-Jen Wang Copyright © 2015 You-Da Hsieh et al. All rights reserved. Characterization of Organic Thin Film Solar Cells of PCDTBT : PC71BM Prepared by Different Mixing Ratio and Effect of Hole Transport Layer Tue, 07 Apr 2015 12:51:23 +0000 http://www.hindawi.com/journals/ijp/2015/687678/ The organic thin film solar cells (OTFSCs) have been successfully fabricated using PCDTBT : PC71BM with different mixing ratios (1 : 1 to 1 : 8) and the influence of hole transport layer thickness (PEDOT : PSS). The active layers with different mixing ratios of PCDTBT : PC71BM have been fabricated using o-dichlorobenzene (o-DCB). The surface morphology of the active layers and PEDOT : PSS layer with different thicknesses were characterized by AFM analysis. Here, we report that the OTFSCs with high performance have been optimized with 1 : 4 ratios of PCDTBT : PC71BM. The power conversion efficiency (PCE = 5.17%) of the solar cells was significantly improved by changing thickness of PEDOT : PSS layer. The thickness of the PEDOT : PSS layer was found to be of significant importance; the thickness of the PEDOT : PSS layer at 45 nm (higher spin speed 5000 rpm) shows higher short circuit current density () and lower series resistance () and higher PCE. Vijay Srinivasan Murugesan, Shusuke Ono, Norio Tsuda, Jun Yamada, Paik-Kyun Shin, and Shizuyasu Ochiai Copyright © 2015 Vijay Srinivasan Murugesan et al. All rights reserved. Prediction of a New Phase of CuxS near Stoichiometric Composition Sun, 05 Apr 2015 11:33:10 +0000 http://www.hindawi.com/journals/ijp/2015/478978/ Cu2S is known to be a promising solar absorber material due to its suitable band gap and the abundance of its constituent elements. Cu2S is known to have complex phase structures depending on the concentration of Cu vacancies. Its instability of phases is due to favorable formation of Cu vacancies and the mobility of Cu atoms within the crystal. Understanding its phase structures is of crucial important for its application as solar absorber material. In this paper, we have predicted a new crystal phase of copper sulfide (CuxS) around chemical composition of by utilizing crystal database search and density functional theory. We have shown that this new crystal phase of CuxS is more favorable than low chalcocite structure even at stoichiometric composition of . However, Cu vacancy formation probability was found to be higher in this new phase than the low chalcocite structure. Prashant Khatri and Muhammad N. Huda Copyright © 2015 Prashant Khatri and Muhammad N. Huda. All rights reserved. Phototreatment of Water by Organic Photosensitizers and Comparison with Inorganic Semiconductors Sun, 05 Apr 2015 07:18:21 +0000 http://www.hindawi.com/journals/ijp/2015/521367/ Phototreatment of water is drawing the attention of many as a promising alternative to replace methods like chlorination, ozonization, and other oxidation processes, used in current disinfection methods limiting harmful side-products and by-products that can cause damage to the fauna and flora. Porphyrins, phthalocyanines, and other related organic dyes are well known for their use in photodynamic therapy (PDT). These photosensitizers cause cell death by generating reactive oxygen species (ROS) especially singlet oxygen in the presence of light. Such molecules are also being explored for photodynamically treating microbial infections, killing of unwanted pathogens in the environment, and oxidation of chemical pollutants. The process of photosensitisation (phototreatment) can be applied for obtaining clean, microbe-free water, thus exploiting the versatile properties of photosensitizers. This review collects the various attempts carried out for phototreatment of water using organic photosensitizers. For comparison, some reports of semiconductors (especially TiO2) used in photocatalytic treatment of water are also mentioned. Merlyn Thandu, Clara Comuzzi, and Daniele Goi Copyright © 2015 Merlyn Thandu et al. All rights reserved. Formation of Silicon Carbide Using Volcanic Ash as Starting Material and Concentrated Sunlight as Energy Resource Mon, 30 Mar 2015 06:18:03 +0000 http://www.hindawi.com/journals/ijp/2015/394605/ SiC was formed using volcanic ash as starting material and concentrated sunlight as energy resource. The solar furnace was composed of two parts: Fresnel lens and reacting furnace. The reacting furnace was composed of a cylindrical vacuum chamber and quartz glass plate functioning to guide the concentrated sunlight into the furnace and was placed at the focal point of the Fresnel lens. The sample was made from the mixture of silica formed from volcanic ash and graphite and placed in the carbon crucible inside the reacting furnace. The temperature in the carbon crucible reached more than 1500°C. After the reaction using concentrated light, β-SiC was formed. The weight % of formed SiC was 90.5%. Kensuke Nishioka, Junki Komori, Kouji Maeda, Yasuyuki Ota, Hiroshi Kaneko, and Kosei Sato Copyright © 2015 Kensuke Nishioka et al. All rights reserved. Investigation of Photovoltaic Assisted Misting System Application for Arbor Refreshment Thu, 26 Mar 2015 12:20:42 +0000 http://www.hindawi.com/journals/ijp/2015/748219/ In this study, for the first time in the literature, solar assisted cooler with misting system established on an arbor with an area of 24 m2 and georeferenced in Elazig (38.6775° N, 39.1707° E), Turkey, is presented. Here, we present a system that reduces interior temperature of the arbor while increasing humidity. Also, the system generates required electricity with a solar photovoltaic module to power pressurized water pump through an inverter and stores it in a battery for use when there is no sunlight. The model of the photovoltaic module was implemented using a Matlab program. As a result of being an uncomplicated system, return on investment for the system is 3.7 years. Hikmet Esen and Omer Tuna Copyright © 2015 Hikmet Esen and Omer Tuna. All rights reserved. An Adaptive Photovoltaic Topology to Overcome Shading Effect in PV Systems Wed, 25 Mar 2015 08:37:28 +0000 http://www.hindawi.com/journals/ijp/2015/294872/ Shading in photovoltaic systems can cause many undesired effects. When shading occurs, the power generated from the PV system is much less than nominal power, increasing the electrical mismatching losses between PV system components. Active research to address this power loss focuses on static and adaptive systems. This paper addresses an adaptive system solution and proposes a new method to adaptively overcome losses due to shading during low radiation conditions. In addition, a statistical analysis for choosing the most feasible and efficient configuration for the system size is presented. The proposed system has been validated under shade conditions in a simulation and prototype experiment. The experiments are conducted using a PV system consisting of 10 PV modules located at the Petroleum Institute in the United Arab Emirates. The proposed system is shown to minimize the shading losses of the PV array in real time by an average of 100% under simulated conditions and 84% in practical experiments. Mohamed Amer Chaaban, Lana El Chaar, and Mahmoud Alahmad Copyright © 2015 Mohamed Amer Chaaban et al. All rights reserved. A New Energy Management Technique for PV/Wind/Grid Renewable Energy System Wed, 25 Mar 2015 06:21:09 +0000 http://www.hindawi.com/journals/ijp/2015/356930/ An intelligent energy management system (IEMS) for maintaining the energy sustainability in renewable energy systems (RES) is introduced here. It consists of wind and photovoltaic (PV) solar panels are established and used to test the proposed IEMS. Since the wind and solar sources are not reliable in terms of sustainability and power quality, a management system is required for supplying the load power demand. The power generated by RES is collected on a common DC bus as a renewable green power pool to be used for supplying power to loads. The renewable DC power bus is operated in a way that there is always a base power available for permanent loads. Then the additional power requirement is supplied from either wind or PV or both depending upon the availability of these power sources. The decision about operating these systems is given by an IEMS with fuzzy logic decision maker proposed in this study. Using the generated and required power information from the wind/PV and load sides, the fuzzy reasoning based IEMS determines the amount of power to be supplied from each or both sources. Besides, the IEMS tracks the maximum power operating point of the wind energy system. Onur Ozdal Mengi and Ismail Hakki Altas Copyright © 2015 Onur Ozdal Mengi and Ismail Hakki Altas. All rights reserved. Synergetic Enhancement of Device Efficiency in Poly(3-hexylthiophene-2,5-diyl)/[6,6]-phenyl C61 Butyric Acid Methyl Ester Bulk Heterojunction Solar Cells by Glycerol Addition in the Active Layer Tue, 24 Mar 2015 13:43:27 +0000 http://www.hindawi.com/journals/ijp/2015/414851/ Poly(3-hexylthiophene-2,5-diyl)(P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PC60BM) is the widely used active layer for the bulk heterojunction solar cells. Annealing is essential for P3HT:PC60BM active layer, since it facilitates the creation of better network for the transfer of the charge carriers. However, the PC60BM in the active layer can crystallize excessively during annealing treatments and disrupt the favorable morphology by forming crystallites in micrometer ranges, thus reducing device efficiency. In this paper we used glycerol as an additive in the active layer. Due to high boiling point of glycerol, it makes slow drying of the active layer possible during the annealing. It thus gives enough time to both electron donor (P3HT) and electron acceptor (PC60BM) components of the active layer to self-organize and also restrict the crystal overgrowth of PC60BM. Further, the glycerol additive makes the active layer smoother, which may also improve adhesion between the electrode and the active layer. The devices with the pristine active layer showed a power conversion efficiency (PCE) of about 2.1% and, with the addition of 30 vol% of glycerol in the active layer, the PCE value increased to 3%. Bobins Augustine and Tapio Fabritius Copyright © 2015 Bobins Augustine and Tapio Fabritius. All rights reserved. Progress in Photovoltaic Devices and Systems Tue, 24 Mar 2015 07:28:16 +0000 http://www.hindawi.com/journals/ijp/2015/926063/ Hongxing Yang, Hui Shen, Tao Xu, and Dimitrios Karamanis Copyright © 2015 Hongxing Yang et al. All rights reserved. Morphological Effect of CNT/Ti Nanocomposite Photoelectrodes Dye-Sensitized Solar Cell on Photovoltaic Performance with Various Annealing Temperatures Thu, 19 Mar 2015 13:51:26 +0000 http://www.hindawi.com/journals/ijp/2015/501978/ This research focused on the fabrication of dye-sensitized solar cell based on a photoanode of carbon nanotube/titanium dioxide (CNT/TiO2) nanocomposite photoanode synthesized through acid-catalyzed sol-gel method. The results show the improvement of the chemical and electrical properties of the solar cells annealed at different temperatures. The CNT/TiO2 colloidal solution was synthesized using titanium tetraisopropoxide and CNT/2-propanol solution. The thin films were doctor-bladed on a fluorine tin oxide glass before being annealed at 550, 650, and 750°C. The field emission scanning electron microscopy morphological images show that the thin films were homogenously distributed and maintained their spherical structures. The X-ray diffraction patterns show that the films consisted of anatase and rutile phases with large crystallite sizes due to temperature increment. The atomic force microscopy analysis presents the thin film roughness in terms of root mean square roughness. The photovoltaic performance was analyzed using IV curve and electrochemical impedance spectroscopy (EIS). The thin films annealed at 750°C had the highest energy conversion efficiency at 5.23%. The EIS analysis estimated the values of the effective electron lifetime (), effective electron diffusion coefficient, effective electron diffusion (), and effective recombination rate constant (). A large , small , and longer can improve photovoltaic performance efficiency. Mohd Zikri Razali, Huda Abdullah, and Izamarlina Asaahari Copyright © 2015 Mohd Zikri Razali et al. All rights reserved. Application of Extension Theory with Chaotic Signal Synchronization on Detecting Islanding Effect of Photovoltaic Power System Tue, 17 Mar 2015 07:26:01 +0000 http://www.hindawi.com/journals/ijp/2015/756313/ The detection of islanding effect is a highly important topic for photovoltaic (PV) power system. The islanding effect occurs when the distributed power source is disconnected from the main supply while the power is still supplied in partial load area, which may injure the set maintenance personnel or damage the equipment. Combining chaotic synchronization and extension theory, this research is to propose a novel detection method to distinguish the occurrence of islanding effect based on nonautonomous Chua’s circuit. To demonstrate the effectiveness of the proposed method, this paper applies PSIM to simulate the PV power system. The experimental results show that the accuracy of the proposed method achieves 98% on islanding effect. Meng-Hui Wang, Mei-Ling Huang, and Kang-Jian Liou Copyright © 2015 Meng-Hui Wang et al. All rights reserved. Effects of CdS Buffer Layers on Photoluminescence Properties of Cu2ZnSnS4 Solar Cells Thu, 12 Mar 2015 11:59:31 +0000 http://www.hindawi.com/journals/ijp/2015/583058/ Cu2ZnSnS4 (CZTS) absorber layers grown by sputtering were investigated by photoluminescence before and after the chemical bath deposition of CdS in order to evaluate the possible passivation of point defects by Cd atoms at the absorber/buffer layer interface. According to the literature, a broad emission around 1.21 eV was observed at low temperature under above bandgap excitation of the as-grown CZTS samples. Broad bands at 1.075 eV and 0.85 eV were detected for the first time under below bandgap excitation of the as-grown CZTS samples at low temperature, which were explained in terms of radiative transitions involving point defect-related levels determined in the literature by first-principles calculations. The emissions observed in the as-grown samples were monitored by both above and below bandgap excitations also in standard CZTS solar cells produced on the same layers. The obtained results suggest that, as in the case of Cu(In, Ga)Se2, Cd atoms passivate point defects at the absorber/buffer layer interface also in CZTS. A. Le Donne, S. Marchionna, P. Garattini, R. A. Mereu, M. Acciarri, and S. Binetti Copyright © 2015 A. Le Donne et al. All rights reserved. Optimal Design of a Secondary Optical Element for a Noncoplanar Two-Reflector Solar Concentrator Thu, 05 Mar 2015 13:11:01 +0000 http://www.hindawi.com/journals/ijp/2015/861353/ This paper presents the results of a parametric design process used to achieve an optimal secondary optical element (SOE) in a noncoplanar solar concentrator composed of two reflectors. The noncoplanar solar concentrator comprises a primary parabolic mirror (M1) and a secondary hyperbolic mirror (M2). The optical performance (i.e., acceptance angle, optical efficiency, and irradiance distribution) of concentrators with various SOEs was compared using ray-tracing simulation. The parametric design process for the SOE was divided into two phases, and an optimal SOE was obtained. The sensitivity to assembly errors of the solar concentrator when using the optimal SOE was studied and the findings are discussed. Yi-Cheng Chen and Chia-Chi You Copyright © 2015 Yi-Cheng Chen and Chia-Chi You. All rights reserved. Photodegradation of Methylene Blue by TiO2-Fe3O4-Bentonite Magnetic Nanocomposite Mon, 02 Mar 2015 08:58:24 +0000 http://www.hindawi.com/journals/ijp/2015/591428/ -bentonite nanoparticles have been prepared by a coprecipitation technique under a nitrogen atmosphere. An aqueous suspension of bentonite was first modified with FeCl2 and FeCl3. TiO2 was then loaded onto the surface of the -bentonite by a sol-gel method. After sufficient drying, the colloidal solution was placed in a muffle furnace at 773 K to obtain the -bentonite composite. The material has been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and vibrating sample magnetometry (VSM). Morphological observation showed that and TiO2 nanoparticles had been adsorbed on the surface of bentonite nanoneedles. The material was then applied for the photodegradation of the azo dye methylene blue (MB). It was found that the removal efficiency of MB exceeded 90% under UV illumination, and that only a 20% mass loss was incurred after six cycles. The composite material thus showed good photocatalytic performance and recycling properties. Wei Chen, Hongyao Xiao, Hang Xu, Tonggang Ding, and Yanmei Gu Copyright © 2015 Wei Chen et al. All rights reserved. Silver Nanoparticles in PEDOT:PSS Layer for Polymer Solar Cell Application Mon, 02 Mar 2015 07:50:05 +0000 http://www.hindawi.com/journals/ijp/2015/764938/ We compare the performance of polymer solar cells based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) with silver nanoparticles (Ag NPs) incorporated in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The structure of constructed solar devices was ITO/PEDOT:PSS:Ag NPs/P3HT:PCBM/Al. Typical polyol chemistry was used to synthesize silver in water solution. Ag nanoparticles were investigated by UV-vis, atomic force microscopy (AFM), and dynamic light scattering (DLS) methods. We investigated influence of amount of silver in a hole transporting layer on the performance of bulk heterojunction polymer solar cells. The value of power conversion efficiency (PCE), equal to 2.16% under simulated 100 mW/cm2 AM 1.5G irradiation, was found for device created in air with 60 µL of Ag NPs added to 1 mL of PEDOT:PSS. Along with the increase amount of Ag NPs from 60 to 150 µL, the PCE decrease was found. Stability of solar cells with Ag was also investigated. The loss in value of PCE after 8 months was found in the range 13–47% depending on the device architecture. The solar cells were additionally measured with impedance spectroscopy. Agnieszka Iwan, Bartosz Boharewicz, Igor Tazbir, Andrzej Sikora, and Beata Zboromirska-Wnukiewicz Copyright © 2015 Agnieszka Iwan et al. All rights reserved. A Multicriteria Analysis of Photovoltaic Systems: Energetic, Environmental, and Economic Assessments Mon, 02 Mar 2015 06:44:50 +0000 http://www.hindawi.com/journals/ijp/2015/627454/ The development of photovoltaic (PV) energy has led to rising efficiencies, better reliability, and falling prices. A multicriteria analysis (MCA) of PV systems is proposed in this paper in order to evaluate the sustainability of alternative projects. The investigations are presented using multiple indicators: Energy Payback Time (EPBT), Energy Return on Investment (EROI), Greenhouse Gas per kilowatt-hour (GHG/kWh), Greenhouse Gas Payback Time (GPBT), Greenhouse Gas Return on Investment (GROI), Net Present Value (NPV), Discounted Payback Time (DPBT), and Discounted Aggregate Cost Benefit (). PV energy is a relevant player in global electricity market and can have a key-role in sustainable growth. Federica Cucchiella and Idiano D’Adamo Copyright © 2015 Federica Cucchiella and Idiano D’Adamo. All rights reserved. Reliability Assessment of Transformerless PV Inverters considering Mission Profiles Sun, 01 Mar 2015 13:30:57 +0000 http://www.hindawi.com/journals/ijp/2015/968269/ Due to the small volume and high efficiency, transformerless inverters have gained much popularity in grid-connected PV applications, where minimizing leakage current injection is mandatory. This can be achieved by either modifying the modulation schemes or adding extra power switching devices, resulting in an uneven distribution of the power losses on the switching devices. Consequently, the device thermal loading is redistributed and thus may alter the entire inverter reliability performance, especially under a long-term operation. In this consideration, this paper assesses the device reliability of three transformerless inverters under a yearly mission profile (i.e., solar irradiance and ambient temperature). The mission profile is translated to device thermal loading, which is used for lifetime prediction. Comparison results reveal the lifetime mismatches among the power switching devices operating under the same condition, which offers new thoughts for a robust design and a reliable operation of grid-connected transformerless PV inverters with high efficiency. Yongheng Yang, Huai Wang, and Frede Blaabjerg Copyright © 2015 Yongheng Yang et al. All rights reserved. Dynamics in Photoexcited DNA Bases and Related Molecules Sun, 01 Mar 2015 07:57:42 +0000 http://www.hindawi.com/journals/ijp/2015/501028/ Yusheng Dou, Zhisong Wang, Fuli Li, and Roland E. Allen Copyright © 2015 Yusheng Dou et al. All rights reserved. Corrigendum to “Expanding Thermal Plasma Chemical Vapour Deposition of ZnO:Al Layers for CIGS Solar Cells” Wed, 25 Feb 2015 14:39:09 +0000 http://www.hindawi.com/journals/ijp/2015/321702/ K. Sharma, B. L. Williams, A. Mittal, H. C. M. Knoops, B. J. Kniknie, N. J. Bakker, W. M. M. Kessels, R. E. I. Schropp, and M. Creatore Copyright © 2015 K. Sharma et al. All rights reserved. Analytical Modelling of High Concentrator Photovoltaic Modules Based on Atmospheric Parameters Mon, 23 Feb 2015 10:18:45 +0000 http://www.hindawi.com/journals/ijp/2015/872163/ The goal of this paper is to introduce a model to predict the maximum power of a high concentrator photovoltaic module. The model is based on simple mathematical expressions and atmospheric parameters. The maximum power of a HCPV module is estimated as a function of direct normal irradiance, cell temperature, and two spectral corrections based on air mass and aerosol optical depth. In order to check the quality of the model, a HCPV module was measured during one year at a wide range of operating conditions. The new proposed model shows an adequate match between actual and estimated data with a root mean square error (RMSE) of 2.67%, a mean absolute error (MAE) of 4.23 W, a mean bias error (MBE) of around 0%, and a determination coefficient () of 0.99. Eduardo F. Fernández, F. Almonacid, T. K. Mallick, and P. Pérez-Higueras Copyright © 2015 Eduardo F. Fernández et al. All rights reserved.