International Journal of Photoenergy http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Review of Polymer, Dye-Sensitized, and Hybrid Solar Cells Sun, 14 Dec 2014 00:11:06 +0000 http://www.hindawi.com/journals/ijp/2014/370160/ The combination of inorganic nanoparticles semiconductor, conjugated polymer, and dye-sensitized in a layer of solar cell is now recognized as potential application in developing flexible, large area, and low cost photovoltaic devices. Several conjugated low bandgap polymers, dyes, and underlayer materials based on the previous studies are quoted in this paper, which can provide guidelines in designing low cost photovoltaic solar cells. All of these materials are designed to help harvest more sunlight in a wider range of the solar spectrum besides enhancing the rate of charge transfer in a device structure. This review focuses on developing solid-state dye-synthesized, polymer, and hybrid solar cells. S. N. F. Mohd-Nasir, M. Y. Sulaiman, N. Ahmad-Ludin, M. A. Ibrahim, K. Sopian, and M. A. Mat-Teridi Copyright © 2014 S. N. F. Mohd-Nasir et al. All rights reserved. UV Blocking Glass: Low Cost Filters for Visible Light Photocatalytic Assessment Mon, 08 Dec 2014 11:52:36 +0000 http://www.hindawi.com/journals/ijp/2014/407027/ A number of commercially available art protection products have been compared and assessed for their suitability as UV blocking filters in the application of “visible light” photocatalytic research. Many groups claiming visible light photocatalytic success employ filters to block out stray UV radiation in order to justify that their photocatalysts are indeed visible light photocatalysts and not UV light photocatalysts. These filters come in varying degrees of ability and price and many authors fail to correctly characterise their filters in individual papers. The use of effective filters to prevent both false positive and false negative results is important to maintain scientific rigor and create accurate understanding of the subject. The optimum UV filter would have the highest UV blocking properties (<390 nm) and simultaneously the highest visible light transmission (390–750 nm). Single and double layers of each of the glass products were assessed as well as laminate products. The conclusions show an inexpensive and highly effective setup for the conduction of visible light photochemistry that should be incorporated as a standard part in any researcher’s work where the claim of visible light activity is made. Charles W. Dunnill Copyright © 2014 Charles W. Dunnill. All rights reserved. Highly Reliable and Low-Cost Fabrication of Warm-White LEDs Using Composite Silica Photonic Crystals Wed, 03 Dec 2014 11:59:05 +0000 http://www.hindawi.com/journals/ijp/2014/846940/ We demonstrated a technique requiring little phosphor that used white light-emitting diodes (WLEDs) containing composite silica colloidal photonic crystals (c-SCPhCs) for developing the warm-WLEDs (w-WLEDs). WLEDs containing c-SCPhCs enhanced luminous efficacy 5.6% more than commercial w-WLEDs did. We used a UV adhesive curing method to improve the adhesion properties of the c-SCPhCs. A reliability analysis (RA) test was performed on the WLEDs containing c-SCPhCs, applying a high temperature and high relative humidity (85°C/85 RH) during WLEDs operation at 120 mA. During a RA test of 2500 h, no visible degradation in optical performance was observed. We implemented a novel, inexpensive technique for producing high luminous flux w-WLEDs that can be used in residential light. Chun-Feng Lai, Yu-Chun Lee, Tzong-Liang Tsai, Chung-Chieh Chang, and Mau-Kuen Wu Copyright © 2014 Chun-Feng Lai et al. All rights reserved. Photocatalysis and Photoelectrochemistry for Solar Fuels Mon, 01 Dec 2014 12:11:30 +0000 http://www.hindawi.com/journals/ijp/2014/640928/ Zhigang Zou, Jinhua Ye, Michael R. Hoffmann, and Wenjun Luo Copyright © 2014 Zhigang Zou et al. All rights reserved. Surfactant-Free Synthesis of Single Crystalline SnS2 and Effect of Surface Atomic Structure on the Photocatalytic Property Mon, 01 Dec 2014 11:45:30 +0000 http://www.hindawi.com/journals/ijp/2014/394146/ Sheetlike tin disulfide (SnS2) single crystal exposed with well-defined facets and flowerlike SnS2 mainly exposed with facets were prepared through a surfactant-free solvothermal process. Photocatalytic degradation of methyl orange (MO) under visible light irradiation indicated that the sheetlike SnS2 showed a much higher activity than flowerlike SnS2. Theoretical and experimental results revealed that the band structure derived from the surface atomic structure played a more important role than the surface energy in the photocatalytic property. The present work has provided a deep insight into the important role of the surface energy and band structure, both of which are derived from the surface atomic structure, in the photocatalytic activity. Mengyi Li, Enzuo Liu, Huilin Hu, Shuxin Ouyang, Hua Xu, and Defa Wang Copyright © 2014 Mengyi Li et al. All rights reserved. Structure, Optical Properties, and Photocatalytic Activity towards H2 Generation and CO2 Reduction of GaN Nanowires via Vapor-Liquid-Solid Process Mon, 01 Dec 2014 07:58:14 +0000 http://www.hindawi.com/journals/ijp/2014/894396/ High quality single crystalline GaN nanowires with large aspect ratio (>100) are synthesized on n-type Si (111) substrate via Au-catalyzed vapor-liquid-solid process. Morphology, crystal structure, and optical property of the as-synthesized GaN nanowires are characterized by means of X-ray diffraction, scanning/transmission electron microscopy, UV-vis diffuse reflection spectroscopy, and room temperature photoluminescence. The results indicate that the as-prepared GaN nanowires with a large aspect ratio are well crystallized in the hexagonal wurtzite structure, and a slight blue shift appears in both the absorption edge and emission peak probably due to the quantization effect. Photocatalytic H2 evolution over the as-prepared GaN nanowires is performed with the incorporation of Pt or Rh as the cocatalyst, exhibiting greatly enhanced capability compared to the GaN powder tested under the same conditions. Moreover, photocatalytic CO2 reduction over the GaN nanowires is also successfully realized using Pt or Rh as the cocatalyst, depending on which the products show a strong selectivity inherently related to the reductive electrons transferred by cocatalyst. Hong Pang, Lequan Liu, Shuxin Ouyang, Hua Xu, Yunxiang Li, and Defa Wang Copyright © 2014 Hong Pang et al. All rights reserved. Preparation of Cerium Modified Titanium Dioxide Nanoparticles and Investigation of Their Visible Light Photocatalytic Performance Mon, 01 Dec 2014 00:10:11 +0000 http://www.hindawi.com/journals/ijp/2014/695679/ Mesoporous Ce/TiO2 nanoparticles have been successfully synthesized using titanate nanotubes as precursor through the hydrothermal-calcination method. The as-prepared materials were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), UV-vis diffuse reflectance spectra and nitrogen adsorption-desorption isotherm analysis. All the obtained Ce/TiO2 materials exhibit anatase phase. Ce element existed in two valance states of Ce3+ and Ce4+. Introduction of Ce species can effectively extend the spectral response from UV to visible light region. N2 adsorption-desorption analysis revealed that all the samples belong to mesoporous structure and have large BET surface area compared with P25. The Ce/TiO2 nanoparticles showed excellent photocatalytic activity in the degradation of MB under visible light irradiation. Jinfeng Liu, Haiyan Li, Qiuye Li, Xiaodong Wang, Min Zhang, and Jianjun Yang Copyright © 2014 Jinfeng Liu et al. All rights reserved. Bottom-Up Enhancement of g-C3N4 Photocatalytic H2 Evolution Utilising Disordering Intermolecular Interactions of Precursor Sun, 30 Nov 2014 13:58:49 +0000 http://www.hindawi.com/journals/ijp/2014/149520/ Disordered intermolecular interaction carbon nitride precursor prepared by water-assisted grinding of dicyandiamide was used for synthesis of g-C3N4. The final sample possesses much looser structure and provides a broadening optical window for effective light harvesting and charge separation efficiency, which exhibits significantly improved H2 evolution by photocatalytic water splitting. The bottom-up mechanochemistry method opens new vistas towards the potential applications of weak interactions in the photocatalysis field and may also stimulate novel ideas completely different from traditional ones for the design and optimization of photocatalysts. Xue Lu Wang, Wen Qi Fang, Yu Hang Li, Pengfei Liu, Haimin Zhang, Yun Wang, Porun Liu, Yefeng Yao, Huijun Zhao, and Hua Gui Yang Copyright © 2014 Xue Lu Wang et al. All rights reserved. Electrochemical Impedance Spectra of Dye-Sensitized Solar Cells: Fundamentals and Spreadsheet Calculation Thu, 27 Nov 2014 14:22:37 +0000 http://www.hindawi.com/journals/ijp/2014/851705/ Electrochemical impedance spectroscopy (EIS) is one of the most important tools to elucidate the charge transfer and transport processes in various electrochemical systems including dye-sensitized solar cells (DSSCs). Even though there are many books and reports on EIS, it is often very difficult to explain the EIS spectra of DSSCs. Understanding EIS through calculating EIS spectra on spreadsheet can be a powerful approach as the user, without having any programming knowledge, can go through each step of calculation on a spreadsheet and get instant feedback by visualizing the calculated results or plot on the same spreadsheet. Here, a brief account of the EIS of DSSCs is given with fundamental aspects and their spreadsheet calculation. The review should help one to develop a basic understanding about EIS of DSSCs through interacting with spreadsheet. Subrata Sarker, A. J. Saleh Ahammad, Hyun Woo Seo, and Dong Min Kim Copyright © 2014 Subrata Sarker et al. All rights reserved. Improved Synthesis of Global Irradiance with One-Minute Resolution for PV System Simulations Wed, 26 Nov 2014 12:58:01 +0000 http://www.hindawi.com/journals/ijp/2014/808509/ High resolution global irradiance time series are needed for accurate simulations of photovoltaic (PV) systems, since the typical volatile PV power output induced by fast irradiance changes cannot be simulated properly with commonly available hourly averages of global irradiance. We present a two-step algorithm that is capable of synthesizing one-minute global irradiance time series based on hourly averaged datasets. The algorithm is initialized by deriving characteristic transition probability matrices (TPM) for different weather conditions (cloudless, broken clouds and overcast) from a large number of high resolution measurements. Once initialized, the algorithm is location-independent and capable of synthesizing one-minute values based on hourly averaged global irradiance of any desired location. The one-minute time series are derived by discrete-time Markov chains based on a TPM that matches the weather condition of the input dataset. One-minute time series generated with the presented algorithm are compared with measured high resolution data and show a better agreement compared to two existing synthesizing algorithms in terms of temporal variability and characteristic frequency distributions of global irradiance and clearness index values. A comparison based on measurements performed in Lindenberg, Germany, and Carpentras, France, shows a reduction of the frequency distribution root mean square errors of more than 60% compared to the two existing synthesizing algorithms. Martin Hofmann, Stefan Riechelmann, Cristian Crisosto, Riyad Mubarak, and Gunther Seckmeyer Copyright © 2014 Martin Hofmann et al. All rights reserved. Effect of UV Irradiation and Temperature on Free Radical Properties in Dehydrocholic and Ursodeoxycholic Acids: An EPR Study Tue, 25 Nov 2014 11:56:06 +0000 http://www.hindawi.com/journals/ijp/2014/953619/ The effect of UV irradiation and temperature on the formation and properties of free radicals in two pharmaceutical important bile acids, such as dehydrocholic (DH) and ursodeoxycholic acids (UDC), was examined. Electron paramagnetic resonance (EPR) spectroscopy was applied to determine the paramagnetic character of UV irradiated and thermally sterilized drugs. Thermal and UV irradiation sterilizations of both compounds were carried out at different conditions according to pharmaceutical norms. The performed EPR measurements of UV irradiated and thermally sterilized DH and UDC samples proved the existence of the complex free radical systems in examined bile acids. Significant influence of UV irradiation in comparison with applied thermal sterilization on free radical concentrations in DH and UDC samples was observed. The results pointed out that thermal method is most suitable for bile acid sterilization. Therefore, this kind of sterilization should be applied in practice. Małgorzata Dołowy, Paweł Ramos, and Barbara Pilawa Copyright © 2014 Małgorzata Dołowy et al. All rights reserved. The Development of LED-Based Dental Light Using a Multiplanar Reflector Design Tue, 18 Nov 2014 08:14:06 +0000 http://www.hindawi.com/journals/ijp/2014/957079/ A multiplanar reflector was designed to enhance the application efficiency of light-emitting diode (LED) light sources that can be employed as LED-based dental lights. This study used a high-power LED developed by Nichia, that is, a single LED capable of providing a total luminous flux of 120 lm, as the primarily light source to design and develop an LED-based dental light. This LED complies with the international standards and regulations stipulated in ISO 9680:2007. The light spots produced by the prototype were rectangular, with a length of 200 mm and a width of 100 mm. These light spots achieved maximum illumination of 12,000 lux. The use of LEDs can reduce energy consumption from 50 W to 3 W, providing an energy saving of more than 90%. Chi-Chang Hsieh and Yan-Huei Li Copyright © 2014 Chi-Chang Hsieh and Yan-Huei Li. All rights reserved. Reversible Visualization for Synchrotron Radiation Using Photochromic Dye and Photostimulable Phosphor Composite Film Tue, 11 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijp/2014/236382/ The study reported herein is undertaken to visualize reversibly synchrotron radiation by using a composite film comprised of two components: a photochromic SP with the conversion characteristics of UV-to-visible color and PSP BaFCl:Eu2+ particles with the conversion characteristics of X-rays-to-UV emission. Kenji Kinashi, Kazuya Jimbo, Takahiro Okabe, Sono Sasaki, and Hiroyasu Masunaga Copyright © 2014 Kenji Kinashi et al. All rights reserved. An Integrated Hybrid Energy Harvester for Autonomous Wireless Sensor Network Nodes Mon, 10 Nov 2014 11:16:01 +0000 http://www.hindawi.com/journals/ijp/2014/760534/ Profiling environmental parameter using a large number of spatially distributed wireless sensor network (WSN) NODEs is an extensive illustration of advanced modern technologies, but high power requirement for WSN NODEs limits the widespread deployment of these technologies. Currently, WSN NODEs are extensively powered up using batteries, but the battery has limitation of lifetime, power density, and environmental concerns. To overcome this issue, energy harvester (EH) is developed and presented in this paper. Solar-based EH has been identified as the most viable source of energy to be harvested for autonomous WSN NODEs. Besides, a novel chemical-based EH is reported as the potential secondary source for harvesting energy because of its uninterrupted availability. By integrating both solar-based EH and chemical-based EH, a hybrid energy harvester (HEH) is developed to power up WSN NODEs. Experimental results from the real-time deployment shows that, besides supporting the daily operation of WSN NODE and Router, the developed HEH is capable of producing a surplus of 971 mA·hr equivalent energy to be stored inside the storage for NODE and 528.24 mA·hr equivalent energy for Router, which is significantly enough for perpetual operation of autonomous WSN NODEs used in environmental parameter profiling. Mukter Zaman, H. Y. Wong, Md. Shabiul Islam, and Nowshad Amin Copyright © 2014 Mukter Zaman et al. All rights reserved. Photobiomodulation 2014 Sun, 09 Nov 2014 11:30:48 +0000 http://www.hindawi.com/journals/ijp/2014/520501/ Timon Cheng-Yi Liu, Quan-Guang Zhang, and Lutz Wilden Copyright © 2014 Timon Cheng-Yi Liu et al. All rights reserved. Design of Multijunction Photovoltaic Cells Optimized for Varied Atmospheric Conditions Thu, 06 Nov 2014 13:39:59 +0000 http://www.hindawi.com/journals/ijp/2014/514962/ Band gap engineering provides an opportunity to not only provide higher overall conversion efficiencies of the reference AM1.5 spectra but also customize PV device design for specific geographic locations and microenvironments based on atmospheric conditions characteristic to that particular location. Indium gallium nitride and other PV materials offer the opportunity for limited bandgap engineering to match spectra. The effects of atmospheric conditions such as aerosols, cloud cover, water vapor, and air mass have been shown to cause variations in spectral radiance that alters PV system performance due to both overrating and underrating. Designing PV devices optimized for spectral radiance of a particular region can result in improved PV system performance. This paper presents a new method for designing geographically optimized PV cells with using a numerical model for bandgap optimization. The geographic microclimate spectrally resolved solar flux for twelve representative atmospheric conditions for the incident radiation angle (zenith angle) of 48.1° and fixed array angle of 40° is used to iteratively optimize the band gap for tandem, triple, and quad-layer of InGaN-based multijunction cells. The results of this method are illustrated for the case study of solar farms in the New York region and discussed. C. Zhang, J. Gwamuri, R. Andrews, and J. M. Pearce Copyright © 2014 C. Zhang et al. All rights reserved. Near Infrared Radiation as a Rapid Heating Technique for TiO2 Films on Glass Mounted Dye-Sensitized Solar Cells Thu, 06 Nov 2014 09:02:29 +0000 http://www.hindawi.com/journals/ijp/2014/953623/ Near infrared radiation (NIR) has been used to enable the sintering of TiO2 films on fluorine-doped tin oxide (FTO) glass in 12.5 s. The 9 µm thick TiO2 films were constructed into working electrodes for dye-sensitized solar cells (DSCs) achieving similar photovoltaic performance to TiO2 films prepared by heating for 30 min in a convection oven. The ability of the FTO glass to heat upon 12.5 s exposure of NIR radiation was measured using an IR camera and demonstrated a peak temperature of 680°C; glass without the 600 nm FTO layer reached 350°C under identical conditions. In a typical DSC heating step, a TiO2 based paste is heated until the polymeric binder is removed leaving a mesoporous film. The weight loss associated with this step, as measured using thermogravimetric analysis, has been used to assess the efficacy of the FTO glass to heat sufficiently. Heat induced interparticle connectivity in the TiO2 film has also been assessed using optoelectronic transient measurements that can identify electron lifetime through the TiO2 film. An NIR treated device produced in 12.5 seconds shows comparable binder removal, electron lifetime, and efficiency to a device manufactured over 30 minutes in a conventional oven. Katherine Hooper, Matthew Carnie, Cecile Charbonneau, and Trystan Watson Copyright © 2014 Katherine Hooper et al. All rights reserved. Effect of Initial Orientation on the Laser-Induced Cycloaddition Reaction of Benzene and Ethylene Mon, 03 Nov 2014 11:41:41 +0000 http://www.hindawi.com/journals/ijp/2014/850641/ The [2 + 2] photocycloaddition reaction of benzene and ethylene was investigated by semiclassical dynamics simulation and complete active space self-consistent field (CASSCF) ab initio calculations. Following laser excitation of the benzene molecule, two mechanisms were observed depending on the location of the second C of ethylene in relation to the hexagonal prism space defined by the first C and the plane of the benzene ring. Synchronous formation of two bonds was observed when the second C is outside the prism space; an asynchronous mechanism is observed otherwise. Charge transfer was observed only in the asynchronous mechanism; CASSCF calculations suggest that the asynchronous mechanism involves a barrierless path from the Frank-Condon point to a conical intersection, while the synchronous mechanism involves 0.8 eV barrier. These results are consistent with a higher quantum yield observed in the simulations for the asynchronous pathway. Shuai Yuan, Huiling Hong, Gang Wang, Wenying Zhang, Weifeng Wu, Yusheng Dou, and Glenn V. Lo Copyright © 2014 Shuai Yuan et al. All rights reserved. Mechanisms of Laser-Induced Reactions of Stacked Benzene Molecules: A Semiclassical Dynamics Simulation and CASSCF Calculation Mon, 27 Oct 2014 12:15:34 +0000 http://www.hindawi.com/journals/ijp/2014/874102/ The response to ultrashort laser pulses of two stacked benzene molecules has been studied by semiclassical dynamics simulation; two typical pathways were found following excitation of one of the benzene molecules by a 25 fs (FWHM), 4.7 eV photon. With a fluence of 40.49 J/m2, the stacked molecules form a cyclobutane benzene dimer; the formation of the two covalent bonds linking two benzenes occurs asynchronously after the excimer decays to electronic ground state. With a fluence of 43.26 J/m2, only one bond is formed, which breaks about 50 fs after formation, followed by separation into the two molecules. The deformation of benzene ring is found to play an important role in the bond cleavage. Kunxian Shu, Jie Zhao, Shuai Yuan, Yusheng Dou, and Glenn V. Lo Copyright © 2014 Kunxian Shu et al. All rights reserved. An Improved Fuzzy Logic Controller Design for PV Inverters Utilizing Differential Search Optimization Wed, 22 Oct 2014 11:31:04 +0000 http://www.hindawi.com/journals/ijp/2014/469313/ This paper presents an adaptive fuzzy logic controller (FLC) design technique for photovoltaic (PV) inverters using differential search algorithm (DSA). This technique avoids the exhaustive traditional trial and error procedure in obtaining membership functions (MFs) used in conventional FLCs. This technique is implemented during the inverter design phase by generating adaptive MFs based on the evaluation results of the objective function formulated by the DSA. In this work, the mean square error (MSE) of the inverter output voltage is used as an objective function. The DSA optimizes the MFs such that the inverter provides the lowest MSE for output voltage and improves the performance of the PV inverter output in terms of amplitude and frequency. The design procedure and accuracy of the optimum FLC are illustrated and investigated using simulations conducted for a 3 kW three-phase inverter in a MATLAB/Simulink environment. Results show that the proposed controller can successfully obtain the desired output when different linear and nonlinear loads are connected to the system. Furthermore, the inverter has reasonably low steady state error and fast response to reference variation. Ammar Hussein Mutlag, Hussain Shareef, Azah Mohamed, M. A. Hannan, and Jamal Abd Ali Copyright © 2014 Ammar Hussein Mutlag et al. All rights reserved. Enhancing the Efficiency of Polymer Solar Cells by Modifying Buffer Layer with N,N-Dimethylacetamide Mon, 20 Oct 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijp/2014/854749/ We modified the PEDOT:PSS anode buffer layer in P3HT:PCBM bulk heterojunction polymer solar cells by spin-coating the solvent N,N-dimethylacetamide (DMAC). This modification significantly enhanced the efficiency of the ITO/PEDOT:PSS/DMAC/P3HT:PCBM/LiF/Al solar cells. The DMAC-treated device spin-coated at 3000 rpm exhibited a power conversion efficiency (PCE) of 3.74%, a 59% improvement over that of an untreated cell. To study the mechanism of improving the conversion efficiency, we characterized many parameters, including the light and dark I-V curves, external quantum efficiency, active layer absorption spectrum, transmission spectrum of ITO:PEDOTPSS, PEDOT:PSS surface morphology, and electrical conductivity. Modifying the PEDOT:PSS film increased conductivity, making it more conducive to hole extraction and collection. Our findings suggest that modifying the anode buffer layer can improve photoelectric conversion efficiency. Shaopeng Yang, Xuefeng Sun, Ye Zhang, Guang Li, Xiaohui Zhao, Xiaowei Li, and Guangsheng Fu Copyright © 2014 Shaopeng Yang et al. All rights reserved. Facile Synthesis of Micron-Sized Hollow Silver Spheres as Substrates for Surface-Enhanced Raman Scattering Sun, 19 Oct 2014 13:45:58 +0000 http://www.hindawi.com/journals/ijp/2014/745913/ A well-designed type of micron-sized hollow silver sphere was successfully synthesized by a simple hard-template method to be used as substrates for surface-enhanced Raman scattering. 4 Å molecular sieves were employed as a removable solid template. [Ag(NH3)2]+ was absorbed as the precursor on the surface of the molecular sieve. Formaldehyde was selected as a reducing agent to reduce [Ag(NH3)2]+, resulting in the formation of a micron-sized silver shell on the surface of the 4 Å molecular sieves. The micron-sized hollow silver spheres were obtained by removing the molecular sieve template. SEM and XRD were used to characterize the structure of the micron-sized hollow silver spheres. The as-prepared micro-silver spheres exhibited robust SERS activity in the presence of adsorbed 4-mercaptobenzoic acid (4-MBA) with excitation at 632.8 nm, and the enhancement factor reached ~1.5 × 106. This synthetic process represents a promising method for preparing various hollow metal nanoparticles. Lixin Xia, Jiarui Xia, Ran Wei, Ying Sui, Zhipeng Sun, Xuehua Song, Peng Song, and Lini Yang Copyright © 2014 Lixin Xia et al. All rights reserved. Enhanced Transformation of Atrazine by High Efficient Visible Light-Driven N, S-Codoped TiO2 Nanowires Photocatalysts Sun, 19 Oct 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijp/2014/425836/ Advanced oxidation process using titanium dioxide as a photocatalyst under solar irradiation is one of the most attractive technologies to eliminate atrazine, an endocrine disrupting and carcinogen contaminant. The N, S-codoped TiO2 nanowires at the calcination of 600°C obtained by a facile hydrothermal method revealed the best photocatalytic performance for the degradation of atrazine under visible light irradiation compared to N, S-codoped TiO2 nanoparticles and S-doped TiO2 nanowires. TOC removal experiment also exhibited the similar result and achieved 63% of atrazine mineralization within 6 h. The degradation of atrazine was driven mainly by •OH and holes during the photocatalytic process. Reactive species quantities such •OH and generated by N, S-codoped TiO2 nanowires under visible light irradiation were much more than those of S-doped TiO2 nanowires and N, S-codoped TiO2 nanoparticles. These results were mainly attributed to the synergistic effect of N and S doping in narrowing the band gap, remarkable increase in electron-hole separation, extending the anatase-to-rutile transformation temperature above 600°C, and preferentially exposing high reactive crystal facets of anatase. Yanlin Zhang, Honghai Wu, and Peihong Liu Copyright © 2014 Yanlin Zhang et al. All rights reserved. Mixing Rules Formulation for a Kinetic Model of the Langmuir-Hinshelwood Semipredictive Type Applied to the Heterogeneous Photocatalytic Degradation of Multicomponent Mixtures Thu, 16 Oct 2014 14:18:11 +0000 http://www.hindawi.com/journals/ijp/2014/817538/ Mixing rules coupled to a semipredictive kinetic model of the Langmuir-Hinshelwood type were proposed to determine the behavior of the heterogeneous solar photodegradation with TiO2-P25 of multicomponent mixtures at pilot scale. The kinetic expressions were expressed in terms of the effective concentration of total organic carbon . An expression was obtained in a generalized form which is a function of the mixing rules as a product of a global contribution of the reaction rate constant and a mixing function . Kinetic parameters of the model were obtained using the Nelder and Mead (N-M) algorithm. The kinetic model was validated with experimental data obtained from the degradation of binary mixtures of chlorinated compounds (DCA: dichloroacetic acid and 4-CP: 4-chlorophenol) at different initial global concentration, using a CPC reactor at pilot scale. A simplex-lattice design experiment was adopted to perform the runs. John Wilman Rodriguez-Acosta, Miguel Ángel Mueses, and Fiderman Machuca-Martínez Copyright © 2014 John Wilman Rodriguez-Acosta et al. All rights reserved. Destruction of Toluene by the Combination of High Frequency Discharge Electrodeless Lamp and Manganese Oxide-Impregnated Granular Activated Carbon Catalyst Mon, 13 Oct 2014 12:41:01 +0000 http://www.hindawi.com/journals/ijp/2014/365862/ The destruction of low concentration of toluene (0–30 ppm) has been studied under the UV/photogenerated O3/MnO2-impregnated granular activated carbon (MnO2-impregnated GAC) process by the combination of self-made high frequency discharge electrodeless lamp (HFDEL) with MnO2-impregnated GAC catalyst. Experimental results showed that the initial toluene concentration can strongly affect the concentration of photogenerated O3 from HFDEL and the efficiency and mass rate of destruction of toluene via HFDEL/MnO2-impregnated GAC system. Active oxygen and hydroxyl radicals generated from HFDEL/MnO2-impregnated GAC system played a key role in the decomposition of toluene process and the intermediates formed by photolysis are more prone to be mineralized by the subsequent MnO2-impregnated GAC catalyst compared to the original toluene, resulting in synergistic mineralization of toluene by HFDEL/MnO2-impregnated GAC system. The role of MnO2-impregnated GAC catalyst is not only to eliminate the residual O3 completely but also to enhance the decomposition and mineralization of toluene. Jianhui Xu, Chaolin Li, Qian Zhang, Di He, Peng Liu, and Yong Ren Copyright © 2014 Jianhui Xu et al. All rights reserved. Solar Hydrogen Production Coupled with the Degradation of a Dye Pollutant Using TiO2 Modified with Platinum and Nafion Mon, 13 Oct 2014 08:12:31 +0000 http://www.hindawi.com/journals/ijp/2014/324859/ The simultaneous production of molecular hydrogen (H2) and degradation of rhodamine B (RhB) was successfully achieved using TiO2 modified with platinum and nafion (Pt/TiO2/Nf) under visible light  nm). Pt/TiO2/Nf exhibited high activity for H2 production in the presence of RhB and EDTA as a photosensitizer (also an organic dye pollutant) and an electron donor, respectively. However, the activity of TiO2 modified with either platinum or nafion for H2 production was negligible under the same experimental conditions. The negatively charged nafion layer enhances the adsorption of cationic RhB and pulls protons, a source of hydrogen, to the surface of TiO2 through electrostatic attraction. On the other hand, platinum deposits on TiO2 can act as an electron sink and a temporary electron reservoir for the reduction of protons. With the production of H2, RhB was gradually degraded through -deethylation, which was confirmed by the spectral blue shift of the maximum absorption wavelength from 556 to 499 nm (corresponding to the of rhodamine 110). With Pt/TiO2/Nf employed at  M (0.6 mol), approximately 70 mol of H2 was produced and RhB and its intermediates were completely removed over a 12 h period. A detailed reaction mechanism was discussed. Jungwon Kim, Yiseul Park, and Hyunwoong Park Copyright © 2014 Jungwon Kim et al. All rights reserved. Preparation of Ni Doped ZnO-TiO2 Composites and Their Enhanced Photocatalytic Activity Mon, 13 Oct 2014 06:34:49 +0000 http://www.hindawi.com/journals/ijp/2014/893158/ Herein, Ni doped ZnO-TiO2 composites were prepared by facile sol-gel approach and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectroscopy (PL). The results indicated that the Ni ions can be incorporated into the lattice of TiO2 structure and replace Ti. The introduction of Ni expanded light absorption of TiO2 to visible region, increased amount of surface hydroxyl groups and physically adsorbed oxygen (as the electronic scavenges), and then enhanced separation rate of photogenerated carriers. The photodegradation test of reactive brilliant blue (KN-R) under simulated solar light indicated that Ni doped ZnO-TiO2 composites have better photocatalytic activities, as compared to those of TiO2 and ZnO-TiO2. Xiaowen Zou, Xiaoli Dong, Limei Wang, Hongchao Ma, Xinxin Zhang, and Xiufang Zhang Copyright © 2014 Xiaowen Zou et al. All rights reserved. Metal/Semiconductor and Transparent Conductor/Semiconductor Heterojunctions in High Efficient Photoelectric Devices: Progress and Features Mon, 22 Sep 2014 06:17:06 +0000 http://www.hindawi.com/journals/ijp/2014/160379/ Metal/semiconductor and transparent conductive oxide (TCO)/semiconductor heterojunctions have emerged as an effective modality in the fabrication of photoelectric devices. This review is following a recent shift toward the engineering of TCO layers and structured Si substrates, incorporating metal nanoparticles for the development of next-generation photoelectric devices. Beneficial progress which helps to increase the efficiency and reduce the cost, has been sequenced based on efficient technologies involved in making novel substrates, TCO layers, and electrodes. The electrical and optical properties of indium tin oxide (ITO) and aluminum doped zinc oxide (AZO) thin films can be enhanced by structuring the surface of TCO layers. The TCO layers embedded with Ag nanoparticles are used to enhance the plasmonic light trapping effect in order to increase the energy harvesting nature of photoelectric devices. Si nanopillar structures which are fabricated by photolithography-free technique are used to increase light-active surface region. The importance of the structure and area of front electrodes and the effect of temperature at the junction are the value added discussions in this review. M. Melvin David Kumar, Ju-Hyung Yun, and Joondong Kim Copyright © 2014 M. Melvin David Kumar et al. All rights reserved. Fabrication and Characterization of Dye-Sensitized Solar Cells for Greenhouse Application Mon, 08 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijp/2014/376315/ We have developed dye-sensitized solar cells using novel sensitizers with enhanced transmittance of red (625–675 nm) and blue (425–475 nm) wavebands to control the illumination condition in the greenhouse. Novel ruthenium bipyridyl sensitizers with general formulas (Me3PhN)4[Ru(dcbpy)2(NCS)2] (JJ-7) and (Me3BnN)4[Ru(dcbpy)2(NCS)2] (JJ-9) have been synthesized and demonstrated as efficient sensitizers in dye-sensitized solar cells for greenhouse application. Under standard AM 1.5 sunlight, the solar cell of JJ-7 using a liquid-based electrolyte exhibits a short-circuit photocurrent density of 8.49 mA/cm2, an open-circuit voltage of 0.83 V, and a fill factor of 0.71, corresponding to an overall conversion efficiency of 4.96% on 5 m TiO2 film. The transmittance of JJ-7 and JJ-9 shows 62.0% and 61.0% at 660 nm and 18.0% and 15.0% at 440 nm for cultivation on 5 m TiO2 film, respectively. Jeum-Jong Kim, Mangu Kang, Ock Keum Kwak, Yong-Jin Yoon, Kil Sik Min, and Moo-Jung Chu Copyright © 2014 Jeum-Jong Kim et al. All rights reserved. Efficiency Enhancement of Nanoporous Silicon/Polycrystalline-Silicon Solar Cells by Application of Trenched Electrodes Sun, 07 Sep 2014 11:48:06 +0000 http://www.hindawi.com/journals/ijp/2014/307643/ Trenched electrodes were proposed to enhance the short-circuit current and conversion efficiency of polycrystalline-silicon (poly-Si) solar cells with nanoporous silicon (NPS) surface layers. NPS films that served as textured surface layers were firstly prepared on heavily doped p+-type (100) poly-Si wafers by anodic etching process. Interdigitated trenches were formed in the NPS layers by a reactive-ion-etch (RIE) process and Cr/Al double-layered metal was then deposited to fill the trenches and construct trenched-electrode-contacts (TEC’s). Cells with TEC structures (called “TEC cells”) obtained 5.5 times higher short-circuit current than that of cells with planar electrode contacts (called “non-TEC cells”). Most significantly, a TEC cell achieved 8 times higher conversion efficiency than that of a non-TEC cell. The enhanced short-circuit current and conversion efficiency in TEC cells were ascribed to the reduced overall series resistance of devices. In a TEC cell, trenched electrodes provided photocurrent flowing routes that directly access the poly-Si substrates without passing through the high resistive NPS layers. Therefore, the application of NPS surface layers with trenched electrodes is a novel approach to development of highly efficient poly-Si solar cells. Kuen-Hsien Wu and Chia-Chun Tang Copyright © 2014 Kuen-Hsien Wu and Chia-Chun Tang. All rights reserved.