International Journal of Photoenergy The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Nanostructured Dielectric Layer for Ultrathin Crystalline Silicon Solar Cells Tue, 16 May 2017 00:00:00 +0000 Nanostructures have been widely used in solar cells due to their extraordinary photon management properties. However, due to poor pn junction quality and high surface recombination velocity, typical nanostructured solar cells are not efficient compared with the traditional commercial solar cells. Here, we demonstrate a new approach to design, simulate, and fabricate whole-wafer nanostructures on dielectric layer on thin c-Si for solar cell light trapping. The optical simulation results show that the periodic nanostructure arrays on dielectric materials could suppress the reflection loss over a wide spectral range. In addition, by applying the nanostructured dielectric layer on 40 μm thin c-Si, the reflection loss is suppressed to below 5% over a wide spectra and angular range. Moreover, a c-Si solar cell with 2.9 μm ultrathin absorber layer demonstrates 32% improvement in short circuit current and 44% relative improvement in energy conversion efficiency. Our results suggest that nanostructured dielectric layer has the potential to significantly improve solar cell performance and avoid typical problems of defects and surface recombination for nanostructured solar cells, thus providing a new pathway towards realizing high-efficiency and low-cost c-Si solar cells. Yusi Chen, Yangsen Kang, Jieyang Jia, Yijie Huo, Muyu Xue, Zheng Lyu, Dong Liang, Li Zhao, and James S. Harris Copyright © 2017 Yusi Chen et al. All rights reserved. Performance Analysis of Photovoltaic Water Heating System Tue, 16 May 2017 00:00:00 +0000 Performance of solar photovoltaic water heating systems with direct coupling of PV array to DC resistive heating elements has been studied and compared with solar photothermal systems. An analysis of optimum fixed load resistance for different climate conditions has been performed for simple PV heating systems. The optimum value of the fixed load resistance depends on the climate, especially on annual solar irradiation level. Use of maximum power point tracking compared to fixed optimized load resistance increases the annual yield by 20 to 35%. While total annual efficiency of the PV water heating systems in Europe ranges from 10% for PV systems without MPP tracking up to 15% for system with advanced MPP trackers, the efficiency of solar photothermal system for identical hot water load and climate conditions is more than 3 times higher. Tomas Matuska and Borivoj Sourek Copyright © 2017 Tomas Matuska and Borivoj Sourek. All rights reserved. Organic Dyes Containing Coplanar Dihexyl-Substituted Dithienosilole Groups for Efficient Dye-Sensitised Solar Cells Thu, 04 May 2017 02:05:37 +0000 A chromophore containing a coplanar dihexyl-substituted dithienosilole (CL1) synthesised for use in dye-sensitised solar cells displayed an energy conversion efficiency of 6.90% under AM 1.5 sunlight irradiation. The new sensitiser showed a similar fill factor and open-circuit voltage when compared with N719. Impedance measurements showed that, in the dark, the charge-transfer resistance of a cell using CL1 in the intermediate-frequency region was higher compared to N719 (69.8 versus 41.3 Ω). Under illumination at AM 1.5G-simulated conditions, the charge-transfer resistances were comparable, indicative of similar recombination rates by the oxidised form of the redox couple. The dye showed instability in ethanol solution, but excellent stability when attached to TiO2. Classical molecular dynamics indicated that interactions between ethanol and the dye are likely to reduce the stability of CL1 in solution form. Time-dependent density functional theory studies were performed to ascertain the absorption spectrum of the dye and assess the contribution of various transitions to optical excitation, which showed good agreement with experimental results. Ciaran Lyons, Neelima Rathi, Pratibha Dev, Owen Byrne, Praveen K. Surolia, Pathik Maji, J. M. D. MacElroy, Aswani Yella, Michael Grätzel, Edmond Magner, Niall J. English, and K. Ravindranathan Thampi Copyright © 2017 Ciaran Lyons et al. All rights reserved. Perovskite Thin Film Solar Cells Based on Inorganic Hole Conducting Materials Wed, 03 May 2017 03:48:50 +0000 Organic-inorganic metal halide perovskites have recently shown great potential for application, due to their advantages of low-cost, excellent photoelectric properties and high power conversion efficiency. Perovskite-based thin film solar cells have achieved a power conversion efficiency (PCE) of up to 20%. Hole transport materials (HTMs) are one of the most important components of perovskite solar cells (PSCs), having functions of optimizing interface, adjusting the energy match, and helping to obtain higher PCE. Inorganic p-type semiconductors are alternative HTMs due to their chemical stability, higher mobility, high transparency in the visible region, and applicable valence band (VB) energy level. This review analyzed the advantages, disadvantages, and development prospects of several popular inorganic HTMs in PSCs. Pan-Pan Zhang, Zheng-Ji Zhou, Dong-Xing Kou, and Si-Xin Wu Copyright © 2017 Pan-Pan Zhang et al. All rights reserved. Improving the Hybrid Photovoltaic/Thermal System Performance Using Water-Cooling Technique and Zn-H2O Nanofluid Tue, 02 May 2017 00:00:00 +0000 This paper presented the improvement of the performance of the photovoltaic panels under Iraqi weather conditions. The biggest problem is the heat stored inside the PV cells during operation in summer season. A new design of an active cooling technique which consists of a small heat exchanger and water circulating pipes placed at the PV rear surface is implemented. Nanofluids (Zn-H2O) with five concentration ratios (0.1, 0.2, 0.3, 0.4, and 0.5%) are prepared and optimized. The experimental results showed that the increase in output power is achieved. It was found that, without any cooling, the measuring of the PV temperature was 76°C in 12 June 2016; therefore, the conversion efficiency does not exceed more than 5.5%. The photovoltaic/thermal system was operated under active water cooling technique. The temperature dropped from 76 to 70°C. This led to increase in the electrical efficiency of 6.5% at an optimum flow rate of 2 L/min, and the thermal efficiency was 60%. While using a nanofluid (Zn-H2O) optimum concentration ratio of 0.3% and a flow rate of 2 L/min, the temperature dropped more significantly to 58°C. This led to the increase in the electrical efficiency of 7.8%. The current innovative technique approved that the heat extracted from the PV cells contributed to the increase of the overall energy output. Hashim A. Hussein, Ali H. Numan, and Ruaa A. Abdulrahman Copyright © 2017 Hashim A. Hussein et al. All rights reserved. Observer-Based Load Frequency Control for Island Microgrid with Photovoltaic Power Wed, 26 Apr 2017 07:13:42 +0000 As renewable energy is widely integrated into the power system, the stochastic and intermittent power generation from renewable energy may cause system frequency deviating from the prescribed level, especially for a microgrid. In this paper, the load frequency control (LFC) of an island microgrid with photovoltaic (PV) power and electric vehicles (EVs) is investigated, where the EVs can be treated as distributed energy storages. Considering the disturbances from load change and PV power, an observer-based integral sliding mode (OISM) controller is designed to regulate the frequency back to the prescribed value, where the neural network observer is used to online estimate the PV power. Simulation studies on a benchmark microgrid system are presented to illustrate the effectiveness of OISM controller, and comparative results also demonstrate that the proposed method has a superior performance for stabilizing the frequency over the PID control. Chaoxu Mu, Weiqiang Liu, Wei Xu, and Md. Rabiul Islam Copyright © 2017 Chaoxu Mu et al. All rights reserved. Feasibility Study of a Building-Integrated PV Manager to Power a Last-Mile Electric Vehicle Sharing System Wed, 26 Apr 2017 00:00:00 +0000 Transportation is one of the largest single sources of air pollution in urban areas. This paper analyzes a model of solar-powered vehicle sharing system using building-integrated photovoltaics (BIPV), resulting in a zero-emission and zero-energy mobility system for last-mile employee transportation. As a case study, an electric bicycle sharing system between a public transportation hub and a work center is modeled mathematically and optimized in order to minimize the number of pickup trips to satisfy the demand, while minimizing the total energy consumption of the system. The whole mobility system is fully powered with BIPV-generated energy. Results show a positive energy balance in e-bike batteries and pickup vehicle batteries in the worst day of the year regarding solar radiation. Even in this worst-case scenario, we achieve reuse rates of 3.8 people per bike, using actual data. The proposed system manages PV energy using only the batteries from the electric vehicles, without requiring supportive energy storage devices. Energy requirements and PV generation have been analyzed in detail to ensure the feasibility of this approach. Manuel Fuentes, Jesús Fraile-Ardanuy, José L. Risco-Martín, and José M. Moya Copyright © 2017 Manuel Fuentes et al. All rights reserved. An Optimal Charging Strategy for PV-Based Battery Swapping Stations in a DC Distribution System Thu, 06 Apr 2017 00:00:00 +0000 Photovoltaic- (PV-) based battery swapping stations (BSSs) utilize a typical integration of consumable renewable resources to supply power for electric vehicles (EVs). The charging strategy of PV-based BSSs directly influences the availability, cost, and carbon emissions of the swapping service. This paper proposes an optimal charging strategy to improve the self-consumption of PV-generated power and service availability while considering forecast errors. First, we introduce the typical structure and operation model of PV-based BSSs. Second, three indexes are presented to evaluate operational performance. Then, a particle swarm optimization (PSO) algorithm is developed to calculate the optimal charging power and to minimize the charging cost for each time slot. The proposed charging strategy helps decrease the impact of forecast uncertainties on the availability of the battery swapping service. Finally, a day-ahead operation schedule, a real-time decision-making strategy, and the proposed PSO charging strategy for PV-based BSSs are simulated in a case study. The simulation results show that the proposed strategy can effectively improve the self-consumption of PV-generated power and reduce charging cost. Shengjun Wu, Qingshan Xu, Qun Li, Xiaodong Yuan, and Bing Chen Copyright © 2017 Shengjun Wu et al. All rights reserved. PV-Powered CoMP-Based Green Cellular Networks with a Standby Grid Supply Tue, 04 Apr 2017 00:00:00 +0000 This paper proposes a novel framework for PV-powered cellular networks with a standby grid supply and an essential energy management technique for achieving envisaged green networks. The proposal considers an emerging cellular network architecture employing two types of coordinated multipoint (CoMP) transmission techniques for serving the subscribers. Under the proposed framework, each base station (BS) is powered by an individual PV solar energy module having an independent storage device. BSs are also connected to the conventional grid supply for meeting additional energy demand. We also propose a dynamic inter-BS solar energy sharing policy through a transmission line for further greening the proposed network by minimizing the consumption from the grid supply. An extensive simulation-based study in the downlink of a Long-Term Evolution (LTE) cellular system is carried out for evaluating the energy efficiency performance of the proposed framework. System performance is also investigated for identifying the impact of various system parameters including storage factor, storage capacity, solar generation capacity, transmission line loss, and different CoMP techniques. Abu Jahid, Abdullah Bin Shams, and Md. Farhad Hossain Copyright © 2017 Abu Jahid et al. All rights reserved. Design and Optimization of Elliptical Cavity Tube Receivers in the Parabolic Trough Solar Collector Thu, 30 Mar 2017 06:32:37 +0000 The nonfragile cavity receiver is of high significance to the solar parabolic trough collector (PTC). In the present study, light distributions in the cavity under different tracking error angles and PTC configurations are analyzed. A new elliptical cavity geometry is proposed and analyzed. It is obtained from this study that light distribution on the tube receiver is asymmetrical when tracking error occurs. On increasing the tracking error angle, more lights are sheltered by the cavity outer surface. The PTC focal distance has negative correlation with the cavity open length, whereas the PTC concentration ratio has positive correlation with the cavity open length. Increasing the tracking error angle and increasing the PTC focal distance would both decrease the cavity blackness. Introducing a flat plate reflector at the elliptical cavity open inlet can largely increase the cavity darkness. Fei Cao, Lei Wang, and Tianyu Zhu Copyright © 2017 Fei Cao et al. All rights reserved. Technoeconomic Evaluation for an Installed Small-Scale Photovoltaic Power Plant Thu, 30 Mar 2017 06:18:09 +0000 Solar energy production and economic evaluation are analyzed, in this study, by using daily solar radiation and average temperature data which are measured for 3 years in the Osmaniye province in Turkey. Besides, this study utilizes the photovoltaic- (PV-) based grid connected to a power plant which has an installed capacity of 1 MW investment in electricity production. Economic values show that the net present value (NPV), the first economic method in the research, is about 111941 USD, which is greater than zero. Therefore, the payback year of this investment is approximately 8.3. The second one of these methods, the payback period of the simple payback period (PBP), is 6.27 years. The last method, which is the mean value of the internal rate of return (IRR), is 10.36%. The results of this study show that Osmaniye is a considerable region for the PV investment in electricity production. As a result, investment of a PV system in Osmaniye can be applicable. Bulent Yaniktepe, Osman Kara, and Coskun Ozalp Copyright © 2017 Bulent Yaniktepe et al. All rights reserved. Synergetic Control of Grid-Connected Photovoltaic Systems Wed, 29 Mar 2017 04:29:01 +0000 It is important to improve the dynamic performance and the low-voltage ride-through (LVRT) capability of a grid-connected photovoltaic (PV) system. This paper presents synergetic control for the control of a grid-connected PV system. Modeling of a grid-connected PV system is described, and differential-algebra equations are obtained. Two control strategies are used in normal operation and during LVRT of a PV system. Practical synergetic controllers with two control strategies are synthesized. The mathematical expressions are derived for computing control variables. The design of the synergetic controllers does not require the linearization of the grid-connected PV system. A grid-connected PV system with synergetic controllers is simulated in Simulink surroundings. The control performance is studied in normal operation and during LVRT. Simulation results show that the synergetic controllers are robust and have good dynamic characteristics under different operation states. Junjie Qian, Kaiting Li, Huaren Wu, Jianfei Yang, and Xiaohui Li Copyright © 2017 Junjie Qian et al. All rights reserved. Effect of the Fe Nanoparticles Generated by Pulsed Plasma in Liquid in the Catalyzed Ozone Removal of Phenolphthalein Tue, 28 Mar 2017 10:39:02 +0000 We have synthesized, in this work, zero valent iron (ZVI) nanoparticles to improve the efficiency of degradation of phenolphthalein catalyzed by ozone in aqueous solution. The Fe nanoparticles were obtained using the pulsed plasma in liquid (PPL) method with water as the liquid medium. Such nanoparticles have a mean size of 12 nm and are composed of ~80% Fe0, while the rest are a mixture of Fe+2 and Fe+3 oxides. The degradation of phenolphthalein was carried on a glass reactor injecting a constant amount of ozone and introducing different concentrations of Fe nanoparticles to the system. When using pure ozone, the percentage of degradation of phenolphthalein measured by colorimetry after one hour of reaction was 84%. However, when Fe nanoparticles are used, such percentage can be as high as 98% in 50 minutes of reaction. Furthermore, the degradation rate constant was 0.0334 min−1 with only ozone and it can be as high as 0.0733 min−1 with Fe nanoparticles. Finally, the total mineralization of phenolphthalein was obtained by total organic carbon (TOC) determinations. It is shown that when using only ozone, we obtained a percentage of mineralization of 49% and 96% when using the highest concentration of Fe nanoparticles. O. Olea-Mejia, M. Fernández-Mondragón, C. Barrera-Díaz, and A. Cabral-Prieto Copyright © 2017 O. Olea-Mejia et al. All rights reserved. A Density Peak-Based Clustering Approach for Fault Diagnosis of Photovoltaic Arrays Tue, 28 Mar 2017 08:40:49 +0000 Fault diagnosis of photovoltaic (PV) arrays plays a significant role in safe and reliable operation of PV systems. In this paper, the distribution of the PV systems’ daily operating data under different operating conditions is analyzed. The results show that the data distribution features significant nonspherical clustering, the cluster center has a relatively large distance from any points with a higher local density, and the cluster number cannot be predetermined. Based on these features, a density peak-based clustering approach is then proposed to automatically cluster the PV data. And then, a set of labeled data with various conditions are employed to compute the minimum distance vector between each cluster and the reference data. According to the distance vector, the clusters can be identified and categorized into various conditions and/or faults. Simulation results demonstrate the feasibility of the proposed method in the diagnosis of certain faults occurring in a PV array. Moreover, a 1.8 kW grid-connected PV system with array is established and experimentally tested to investigate the performance of the developed method. Peijie Lin, Yaohai Lin, Zhicong Chen, Lijun Wu, Lingchen Chen, and Shuying Cheng Copyright © 2017 Peijie Lin et al. All rights reserved. One-Pot Solid-State Reaction Approach to Synthesize Ag-Cu2O/GO Ternary Nanocomposites with Enhanced Visible-Light-Responsive Photocatalytic Activity Tue, 28 Mar 2017 00:00:00 +0000 A facile ball milling-assisted solid-state reaction method was developed to synthesize Ag-Cu2O/graphene oxide (GO) nanocomposites. In the resultant complex heterostructures, Ag nanocrystals were mainly deposited on the surface of Cu2O, while Ag-Cu2O composites were anchored onto GO sheets. The resultant Ag-Cu2O/GO nanocomposites exhibited excellent photocatalytic activity with 90% of methyl orange (MO) dye degradation efficiency after 60 min of visible-light irradiation, which was much higher than that of either Cu2O or Ag-Cu2O. This study opens a new avenue to fabricate visible-light-responsive photocatalyst with high performance for environmental pollution purification. Longfeng Li, Jing Zhang, Xianliang Fu, Peipei Xiao, Maolin Zhang, and Mingzhu Liu Copyright © 2017 Longfeng Li et al. All rights reserved. Recent Developments of Photovoltaics Integrated with Battery Storage Systems and Related Feed-In Tariff Policies: A Review Thu, 16 Mar 2017 08:22:58 +0000 The paper presents a review of the recent developments of photovoltaics integrated with battery storage systems (PV-BESs) and related to feed-in tariff policies. The integrated photovoltaic battery systems are separately discussed in the regulatory context of Germany, Italy, Spain, United Kingdom, Australia, and Greece; the attention of this paper is focused on those integrated systems subject to incentivisation policies such as feed-in tariff. Most of the contributions reported in this paper consider already existing incentive schemes; the remaining part of the contributions proposes interesting and novel feed-in tariff schemes. All the contributions provide an important resource for carrying out further research on a new era of incentive policies in order to promote storage technologies and integrated photovoltaic battery systems in smart grids and smart cities. Recent incentive policies adopted in Germany, Italy, Spain, and Australia are also discussed. Angel A. Bayod-Rújula, Alessandro Burgio, Zbigniew Leonowicz, Daniele Menniti, Anna Pinnarelli, and Nicola Sorrentino Copyright © 2017 Angel A. Bayod-Rújula et al. All rights reserved. Influence of Front and Back Contacts on Photovoltaic Performances of p-n Homojunction Si Solar Cell: Considering an Electron-Blocking Layer Sun, 12 Mar 2017 06:59:08 +0000 In this simultion work, the effect of front and back contacts of p-n homojunction Si solar cell with an electron-blocking layer (EBL) has been studied with the help of a strong solar cell simulator named AMPS-1D (analysis of microelectronic and photonic structures one dimensional). Without the effect of these contact parameters, low solar cell efficiency has been observed. Fluorine-doped tin oxide (FTO) with high work function (5.45 eV) has been used as the front contact to the proposed solar cell. Zinc (Zn) metal which has a work function of 4.3 eV has been used as the back contact of the proposed model. With FTO as the front contact and Zn as the back contact, the optimum efficiency of 29.275% (Voc = 1.363 V, Jsc = 23.747 mA/cm2, FF = 0.905) has been observed. This type of simple Si-based p-n homojunction solar cell with EBL of high efficiency has been proposed in this paper. Md. Feroz Ali and Md. Faruk Hossain Copyright © 2017 Md. Feroz Ali and Md. Faruk Hossain. All rights reserved. Non-Toxic Buffer Layers in Flexible Cu(In,Ga)Se2 Photovoltaic Cell Applications with Optimized Absorber Thickness Wed, 01 Mar 2017 00:00:00 +0000 Absorber layer thickness gradient in Cu(In1−xGax)Se2 (CIGS) based solar cells and several substitutes for typical cadmium sulfide (CdS) buffer layers, such as ZnS, ZnO, ZnS(O,OH), Zn1−xSnxOy (ZTO), ZnSe, and In2S3, have been analyzed by a device emulation program and tool (ADEPT 2.1) to determine optimum efficiency. As a reference type, the CIGS cell with CdS buffer provides a theoretical efficiency of 23.23% when the optimum absorber layer thickness was determined as 1.6 μm. It is also observed that this highly efficient CIGS cell would have an absorber layer thickness between 1 μm and 2 μm whereas the optimum buffer layer thickness would be within the range of 0.04–0.06 μm. Among all the cells with various buffer layers, the best energy conversion efficiency of 24.62% has been achieved for the ZnO buffer layer based cell. The simulation results with ZnS and ZnO based buffer layer materials instead of using CdS indicate that the cell performance would be better than that of the CdS buffer layer based cell. Although the cells with ZnS(O,OH), ZTO, ZnSe, and In2S3 buffer layers provide slightly lower efficiencies than that of the CdS buffer based cell, the use of these materials would not be deleterious for the environment because of their non-carcinogenic and non-toxic nature. Md. Asaduzzaman, Md. Billal Hosen, Md. Karamot Ali, and Ali Newaz Bahar Copyright © 2017 Md. Asaduzzaman et al. All rights reserved. Influence of the Porosity of the TiO2 Film on the Performance of the Perovskite Solar Cell Wed, 01 Feb 2017 06:41:17 +0000 The structure of mesoporous TiO2 (mp-TiO2) films is crucial to the performance of mesoporous perovskite solar cells (PSCs). In this study, we fabricated highly porous mp-TiO2 films by doping polystyrene (PS) spheres in TiO2 paste. The composition of the perovskite films was effectively improved by modifying the mass fraction of the PS spheres in the TiO2 paste. Due to the high porosity of the mp-TiO2 film, PbI2 and CH3NH3I could sufficiently infiltrate into the network of the mp-TiO2 film, which ensured a more complete transformation to CH3NH3PbI3. The surface morphology of the mp-TiO2 film and the photoelectric performance of the perovskite solar cells were investigated. The results showed that an increase in the porosity of the mp-TiO2 film resulted in an improvement in the performance of the PSCs. The best device with the optimized mass fraction of 1.0 wt% PS in TiO2 paste exhibited an efficiency of 12.69%, which is 25% higher than the efficiency of the PSCs without PS spheres. Xiaodan Sun, Jia Xu, Li Xiao, Jing Chen, Bing Zhang, Jianxi Yao, and Songyuan Dai Copyright © 2017 Xiaodan Sun et al. All rights reserved. Investigation on the Synthesis and Photocatalytic Property of Uranyl Complexes of the -Diketonates Biscatecholamide Ligand Sun, 29 Jan 2017 08:08:05 +0000 A series of uranyl complexes have been synthesized by reacting hexadentate ligands CH2[COO (CH2)nCAM; , 3, 4]2 [CAM = 2,3-Ph(OH)2CONH] containing the catecholamide (CAM) group and β-diketonates framework with uranyl nitrate. They were characterized by FTIR, UV-vis, 1H NMR, XPS, TGA, and elemental analysis. The analysis revealed that oxygen atom of β-diketonate did not bind to uranyl ion in complexes 1–3. The photocatalytic degradation properties of the target complexes for degradation of rhodamine B (RhB) were investigated. The result indicated that approximately 74%, 71%, and 67% RhB were degraded in the presence of complexes 1–3 after about 210 min, respectively. Consequently, complexes 1–3 have excellent photocatalytic degradation property. Qingchun Zhang, Bo Jin, Rufang Peng, Xiaofang Wang, Zhaotao Shi, Qiangqiang Liu, Shan Lei, and Hua Liang Copyright © 2017 Qingchun Zhang et al. All rights reserved. Copper Sulfide Catalyzed Porous Fluorine-Doped Tin Oxide Counter Electrode for Quantum Dot-Sensitized Solar Cells with High Fill Factor Thu, 26 Jan 2017 12:28:12 +0000 The performance of quantum dot-sensitized solar cell (QDSSC) is mainly limited by chemical reactions at the interface of the counter electrode. Generally, the fill factor (FF) of QDSSCs is very low because of large charge transfer resistance at the interface between the counter electrode and electrolyte solution containing redox couples. In the present research, we demonstrate the improvement of the resistance by optimization of surface area and amount of catalyst of the counter electrode. A facile chemical synthesis was used to fabricate a composite counter electrode consisting of fluorine-doped tin oxide (FTO) powder and CuS nanoparticles. The introduction of a sputtered gold layer at the interface of the porous-FTO layer and underlying glass substrate also markedly reduced the resistance of the counter electrode. As a result, we could reduce the charge transfer resistance and the series resistance, which were 2.5 [Ω] and 6.0 [Ω], respectively. This solar cell device, which was fabricated with the presently designed porous-FTO counter electrode as the cathode and a PbS-modified electrode as the photoanode, exhibited a FF of 58%, which is the highest among PbS-based QDSSCs reported to date. Satoshi Koyasu, Daiki Atarashi, Etsuo Sakai, and Masahiro Miyauchi Copyright © 2017 Satoshi Koyasu et al. All rights reserved. Performance Enhancement of Dye-Sensitized Solar Cells Using a Natural Sensitizer Tue, 24 Jan 2017 05:58:32 +0000 Dye-sensitized solar cells (DSSCs) based on natural sensitizers have become a topic of significant research because of their urgency and importance in the energy conversion field and the following advantages: ease of fabrication, low-cost solar cell, and usage of nontoxic materials. In this study, the chlorophyll extracted from papaya leaves was used as a natural sensitizer. Dye molecules were adsorbed by TiO2 nanoparticle surfaces when submerged in the dye solution for 24 h. The concentration of the dye solution influences both the amount of dye loading and the DSSC performance. The amount of adsorbed dye molecules by TiO2 nanoparticle was calculated using a desorption method. As the concentration of dye solution was increased, the dye loading capacity and power conversion efficiency increased. Above 90 mM dye solution concentration, however, the DSSC efficiency decreased because dye precipitated on the TiO2 nanostructure. These characteristics of DSSCs were analyzed under the irradiation of 100 mW/cm2. The best performance of DSSCs was obtained at 90 mM dye solution, with the values of , ,  FF, and efficiency of DSSCs being 0.561 V, 0.402 mA/cm2, 41.65%, and 0.094%, respectively. Zainal Arifin, Sudjito Soeparman, Denny Widhiyanuriyawan, and Suyitno Suyitno Copyright © 2017 Zainal Arifin et al. All rights reserved. Mismatch Based Diagnosis of PV Fields Relying on Monitored String Currents Mon, 16 Jan 2017 00:00:00 +0000 This paper presents a DC side oriented diagnostic method for photovoltaic fields which operates on string currents previously supplied by an appropriate monitoring system. The relevance of the work relies on the definition of an effective and reliable day-by-day target for the power that every string of the field should have produced. The procedure is carried out by comparing the instantaneous power produced by all solar strings having the same orientation and by attributing, as producible power for all of them, the maximum value. As figure of merit, the difference between the maximum allowed energy production (evaluated as the integral of the power during a defined time interval) and the energy actually produced by the strings is defined. Such a definition accounts for both weather and irradiance conditions, without needing additional sensors. The reliability of the approach was experimentally verified by analyzing the performance of two medium size solar fields that were monitored over a period of four years. Results allowed quantifying energy losses attributable to underperforming solar strings and precisely locating their position in the field. Pierluigi Guerriero, Luigi Piegari, Renato Rizzo, and Santolo Daliento Copyright © 2017 Pierluigi Guerriero et al. All rights reserved. Monitoring, Diagnosis, and Power Forecasting for Photovoltaic Fields: A Review Wed, 11 Jan 2017 12:54:18 +0000 A wide literature review of recent advance on monitoring, diagnosis, and power forecasting for photovoltaic systems is presented in this paper. Research contributions are classified into the following five macroareas: (i) electrical methods, covering monitoring/diagnosis techniques based on the direct measurement of electrical parameters, carried out, respectively, at array level, single string level, and single panel level with special consideration to data transmission methods; (ii) data analysis based on artificial intelligence; (iii) power forecasting, intended as the ability to evaluate the producible power of solar systems, with emphasis on temporal horizons of specific applications; (iv) thermal analysis, mostly with reference to thermal images captured by means of unmanned aerial vehicles; (v) power converter reliability especially focused on residual lifetime estimation. The literature survey has been limited, with some exceptions, to papers published during the last five years to focus mainly on recent developments. S. Daliento, A. Chouder, P. Guerriero, A. Massi Pavan, A. Mellit, R. Moeini, and P. Tricoli Copyright © 2017 S. Daliento et al. All rights reserved. Silver/Carbon Codoped Titanium Dioxide Photocatalyst for Improved Dye Degradation under Visible Light Wed, 11 Jan 2017 00:00:00 +0000 Herein, we report the synthesis of quartz supported TiO2 photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO2 with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO2 photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO2 using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO2 and also all codoped TiO2 photocatalysts under visible light irradiation. P. Nyamukamba, L. Tichagwa, S. Mamphweli, and L. Petrik Copyright © 2017 P. Nyamukamba et al. All rights reserved. Enhanced Efficiency of PTB7 : PC61BM Organic Solar Cells by Adding a Low Efficient Polymer Donor Wed, 11 Jan 2017 00:00:00 +0000 Ternary blend polymer solar cells combining two electron-donor polymers, poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl] (PTB7) and poly[2,5-bis(3-dodecylthiophen-2-yl)thieno[3,2-b]thiophene] (pBTTT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), as electron-acceptor, were fabricated. The power conversion efficiency of the ternary cells was enhanced by 18%, with respect to the reference binary cells, for a blend composition with 25% (wt%) of pBTTT in the polymers content. The optimized device performance was related to the blend morphology, nonrevealing pBTTT aggregates, and improved charge extraction within the device. Joana Farinhas, Ricardo Oliveira, Quirina Ferreira, Jorge Morgado, and Ana Charas Copyright © 2017 Joana Farinhas et al. All rights reserved. Effect of Modulating Spin-Coating Rate of TiO2 Precursor for Mesoporous Layer on Hysteresis of Solar Cells with Polar CH3NH3PbI3 Perovskite Thin Film Tue, 10 Jan 2017 12:35:08 +0000 Compared with the crystalline Si solar cells, the - characteristics of CH3NH3PbI3 perovskite solar cells are different under forward and reverse scan, and the CH3NH3PbI3 film exhibits some polarization properties. To explore those performances of the mesoporous TiO2 layer based perovskite solar cells, we focus on the effect of modulating the spin-coating rate of the TiO2 precursor for mesoporous layer on - hysteresis of solar cells with the polar film by - curves, atomic force microscopy topographic images, and piezoresponse force microscopy phase images. Firstly, the AFM images illustrate that the polarization behaviors exist and the deformation scale is large at the corresponding position when the DC bias voltage increases. Secondly, it is suggested that the polar films which applied the positive DC biases voltage show a tendency to 0° phase angle, while the polar films which applied the negative DC biases voltage show a tendency to −180° phase angle. Thirdly, a weak polar hysteresis loop relation for CH3NH3PbI3 film was observed. Finally, the hysteresis index for the 1500 rpm mesostructured solar cell shows relatively low - hysteresis compared with the 3000 rpm mesostructured and the planar-structured solar cell. Our experimental results bring novel routes for reducing the hysteresis and investigating the polar nature for CH3NH3PbI3 material. Qi Li, Xiaoping Zou, Yuanyuan Li, Yaxian Pei, Shuangxiong Zeng, and Dongdong Guo Copyright © 2017 Qi Li et al. All rights reserved. Synergetic Enhancement of the Photocatalytic Activity of TiO2 with Visible Light by Sensitization Using a Novel Push-Pull Zinc Phthalocyanine Tue, 10 Jan 2017 11:27:00 +0000 A new one-pot synthesis of a novel A3B-type asymmetric zinc phthalocyanine (AZnPc) was developed. The phthalocyanine complex was characterized unambiguously and used to prepare a TiO2 hybrid photocatalyst to enhance its photocatalytic activity in the visible range. Different compositions of the phthalocyanine dye were tested in order to find the optimum amount of sensitizer to get the highest activity during the photocatalytic tests. The hybrid photocatalyst was characterized by UV-Vis diffuse reflectance (DRS) and Fourier transform infrared spectroscopy (FT-IR) and its photocatalytic activity was compared with that of the individual components considering the effects of sensitization on their efficiency to degrade Rhodamine B as a model reaction. A synergic improvement of the photocatalytic activity for the hybrid system was explained in terms of an improved electron injection from the photo-activated phthalocyanine to the TiO2. Considering the structural features of the phthalocyanine sensitizer and their effect on aggregation, some mechanistic aspects of its binding to TiO2 are suggested to account for the photocatalytic activity enhancement. Finally, the inhibitory effect on the sprouting of chia seeds (Salvia hispanica) was evaluated in order to test the toxicity of the water effluent obtained after the photodegradation process. According to our growth inhibition assays, it was found that the Rh-B degradation by-products do not lead to an acute toxicity. A. Luna-Flores, M. A. Valenzuela, J. A. Luna-López, A. D. Hernández de la Luz, L. C. Muñoz-Arenas, M. Méndez-Hernández, and J. L. Sosa-Sánchez Copyright © 2017 A. Luna-Flores et al. All rights reserved. Sprayed and Spin-Coated Multilayer Antireflection Coating Films for Nonvacuum Processed Crystalline Silicon Solar Cells Mon, 02 Jan 2017 14:43:00 +0000 Using the simple and cost-effective methods, spin-coated ZrO2-polymer composite/spray-deposited TiO2-compact multilayer antireflection coating film was introduced. With a single TiO2-compact film on the surface of a crystalline silicon wafer, 5.3% average reflectance (the reflectance average between the wavelengths of 300 nm and 1100 nm) was observed. Reflectance decreased further down to 3.3% after forming spin-coated ZrO2 on the spray-deposited TiO2-compact film. Silicon solar cells were fabricated using CZ-Si p-type wafers in three sets: (1) without antireflection coating (ARC) layer, (2) with TiO2-compact ARC film, and (3) with ZrO2-polymer composite/TiO2-compact multilayer ARC film. Conversion efficiency of the cells improved by a factor of 0.8% (from 15.19% to 15.88%) owing to the multilayer ARC. was improved further by 2 mA cm−2 (from 35.3 mA cm−2 to 37.2 mA cm−2) when compared with a single TiO2-compact ARC. Abdullah Uzum, Masashi Kuriyama, Hiroyuki Kanda, Yutaka Kimura, Kenji Tanimoto, Hidehito Fukui, Taichiro Izumi, Tomitaro Harada, and Seigo Ito Copyright © 2017 Abdullah Uzum et al. All rights reserved. Study on the Optimizing Operation of Exhaust Air Heat Recovery and Solar Energy Combined Thermal Compensation System for Ground-Coupled Heat Pump Sun, 01 Jan 2017 09:25:37 +0000 This study proposed an exhaust air heat recovery and solar energy combined thermal compensation system (ESTC) for ground-coupled heat pumps. Based on the prediction of the next day’s exhaust air temperature and solar irradiance, an optimized thermal compensation (OTC) method was developed in this study as well, in which the exhaust air heat recovery compensator and solar energy compensator in the ESTC system run at high efficiency throughout various times of day. Moreover, a modified solar term similar days group (STSDG) method was proposed to improve the accuracy of solar irradiance prediction in hazy weather. This modified STSDG method was based on air quality forecast and AQI (air quality index) correction factors. Through analyzing the operating parameters and the simulation results of a case study, the ESTC system proved to have good performance and high efficiency in eliminating the heat imbalance by using the OTC method. The thermal compensation quantity per unit energy consumption (TEC) of ESTC under the proposed method was 1.25 times as high as that under the traditional operation method. The modified STSDG method also exhibited high accuracy. For the accumulated solar irradiance of the four highest daily radiation hours, the monthly mean absolute percentage error (MAPE) between the predicted values and the measured values was 6.35%. Kuan Wang, Nianping Li, Jinqing Peng, and Yingdong He Copyright © 2017 Kuan Wang et al. All rights reserved.