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Al
En savoir plusPublication year: 2012 Source: Current Applied Physics, Volume 12, Issue 2, March 2012, Pages 380-384 K. Nagamani, N. Revathi, P. Prathap, Y. Lingappa, K.T. Ramakrishna Reddy ZnS is one of the potential candidates as a window/buffer layer for solar photovoltaic applications. Al-doped ZnS nanocrystalline films were grown by a simple and economic process, chemical solution growth method. The layers were prepared for different Al-dopant concentrations that vary in the range, 0–10 at. %. The effect of Al-doping on the composition, structure, optical, electrical and photoluminescence properties of the synthesized layers was determined using appropriate techniques. The elemental composition of a typical sample with 6 at. % ‘Al’ in ZnS was Zn = 44.9 at. %,S = 49.8 at. % and Al = 5.3 at. %. The films were nanocrystalline in nature and showed (111) plane of ZnS as the preferred orientation for all the doping concentrations. The layers with 6 at. % of Al showed a crystallite size of ~9 nm. The FTIR studies confirmed the presence of ZnS in the layers. The layers showed an average transmittance of ~75% in the visible region. The change of photoluminescence behaviour with dopant concentration was also studied. The electrical resistivity was considerably decreased from 10 Ocm to 10 Ocm with Al-doping. The detailed analysis of results will be presented and discussed. Highlights ? Deposition of ZnS:Al films by solution growth method varying Al-doping content. ? Investigation of the physical and chemical properties of annealed ZnS:Al layers. ? Study of photoluminescence in ZnS:Al layers to identify the defect states. ? Formation of ZnS:Al films with low electrical resistivity for solar cell application.
Date : 18/01/2012 - Editeur : ScienceDirect
Investment appraisal of a small, grid-connected photovoltaic plant under the Serbian feed
En savoir plusPublication year: 2012 Source: Renewable and Sustainable Energy Reviews, Volume 16, Issue 3, April 2012, Pages 1673-1682 Sanja Stevanovic, Mila Pucar Serbian government has recently introduced the system of feed-in tariffs for electricity generated from renewable sources. The proposed feed-in tariff for photovoltaic electricity is set to 0.23 €/kWh paid for 12 years, with the PV electricity produced after the first 12 years being sold at the grid electricity market price for the rest of the plant lifetime. Although such FIT could have been justified by the small, average retail grid electricity price of just 0.054 €/kWh for Serbian households, the investment appraisal of a real case of 2.82 kWp PV power plant in two Serbian cities of Zlatibor and Negotin, clearly illustrates that the proposed FIT framework is not sufficient to attract investments into PV in Serbia. In the second part of the paper, we have analyzed alternative, more reasonable feed-in tarrif frameworks, with the goal of selecting those able to sustain the PV adoption and diffusion in Serbia.
Date : 18/01/2012 - Editeur : ScienceDirect
An integrative approach to the design methodology for 3-phase power conditioners in Photovoltaic Grid
En savoir plusPublication year: 2012 Source: Energy Conversion and Management, Volume 56, April 2012, Pages 80-95 Alexis B. Rey-Boué, Rafael García-Valverde, Francisco de A. Ruz-Vila, José M. Torrelo-Ponce A novel methodology is presented in this paper, for the design of the Power and Control Subsystems of a 3-phase Photovoltaic Grid-Connected system in an easy and comprehensive way, as an integrative approach. At the DC side of the Power Subsystem, the Photovoltaic Generator modeling is revised and a simple model is proposed, whereas at the AC side, a vector analysis is done to deal with the instantaneous 3-phase variables of the grid-connected Voltage Source Inverter. Ad–qcontrol approach is established in the Control Subsystem, along with its specific tuned parameters, as a vector control alternative which will allow the decoupled control of the instantaneous active and reactive powers. A particular Case of Study is presented to illustrate the behavior of the design methodology regarding the fulfillment of the Photovoltaic plant specifications. Some simulations are run to study the performance of the Photovoltaic Generator together with the exertedd–qcontrol to the grid-connected 3-phase inverter, and some experimental results, obtained from a built flexible platform, are also shown. The simulations and the experimental results validate the overall performance of the 3-phase Photovoltaic Grid-Connected system due to the attained unitary power factor operation together with good power quality. The final validation of the proposed design methodology is also achieved. Highlights ? A design methodology for Photovoltaic grid-connected systems is presented. ? Models of the Photovoltaic Generator and the 3-phase Inverter are described. ? The power factor and the power quality are regulated with vector control. ? Simulation and experimental results validate the design methodology. ? The proposed methodology can be extended to any Renewable or Industrial System.
Date : 18/01/2012 - Editeur : ScienceDirect
Investigation of a broadband TiO2/SiO2optical thin
En savoir plusPublication year: 2012 Source: Applied Energy, Volume 92, April 2012, Pages 298-306 Chunhui Shou, Zhongyang Luo, Tao Wang, Weidong Shen, Gary Rosengarten, ... Using the technology of spectral selectivity to integrate different solar power generators in a hybrid system is a feasible way to improve the optical-electric efficiency. This paper presents an 82-layer broadband optical interference thin-film filter matching with crystalline silicon photovoltaic cells, which using TiO2and SiO2as fabrication materials and can be used in hybrid solar power systems like photovoltaic–thermoelectric generator (PV–TEG) systems. The design, optimization and fabrication process of the filter is described, high reflectance from 400 nm to 1100 nm as well as high transmittance from 1100 nm to 2500 nm over the broadband of solar spectrum are obtained. The classical electron beam evaporation plant is used to fabricate the filter. Four different incidence angles’ optical performances of the sample filter are measured which agree well with the numerical simulation results. The electrical characteristics of a typical Silicon photovoltaic cell using the fabricated sample filter are measured. An average efficiency increase of 3.24% for the solar cell with respect to the solar energy it receives can be obtained due to the filter. A calculation model for a hybrid PV–TEG system using this thin-film filter is proposed and the benefits of the filter for hybrid solar power systems are demonstrated. Highlights ? We present a new optical filter to get optimal performance of PV power system. ? The experimental results of the filter fabrication match well with numerical design. ? The measured results of a typical Si cell show efficiency increase using the filter. ? A proposed model for hybrid PV–TEG system demonstrates the benefits of the filter.
Date : 18/01/2012 - Editeur : ScienceDirect
A comparison of 15 polymers for application in photovoltaic modules in PV
En savoir plusPublication year: 2012 Source: Applied Energy, Volume 92, April 2012, Pages 286-297 T. Gorter, A.H.M.E. Reinders Autonomous electric propulsion in boats by photovoltaic power is an upcoming technology which sets specific requirements to the integration of crystalline PV cells in boat surfaces, such as the deck. Light weight and flexibility of shape as well as endurance are required for successful PV-powered boat design. In order to find alternative materials for common glass and EVA laminates, we evaluated 15 polymers, some with glass fiber reinforcement (GFR), of which we assume they might be suitable for use as a replacement of glass in PV modules for recreational PV boats. The mechanical and optical properties and specific demands due to application in boats have been listed for these 15 polymers as well as variations with glass fiber reinforcement. Costs related to the thickness of polymers and GFR polymers have been taken into account. Our evaluation shows that some polymer materials that have been reinforced with glass fibers such as fluorides, show potential to be used as photovoltaic module materials. Epoxies and GFR epoxies show to be good alternatives when considering cost and weight reduction of PV modules. They offer high strength when thickness remains under 4 mm. For epoxies, this would lead to a weight around 20 g/Wp to 25 g/Wp compared to a weight around 86 g/Wp to 130 g/Wp for PV glass laminates. Fluorides offer excellent UV-stability but are up to 20 times more expensive per kilogram and require structural support compared to glass. They prove to offer high energy conversion performance by having high UV stability and high transmittance. To be cost competitive with glass, the thickness of fluorides should be under 1 mm. This could lead to a weight per Wattpeak ratio of 10 g/Wp to 15 g/Wp, which is a reduction of 85% compared to PV glass laminates. Highlights ? PV boats need light weight c-Si PV modules to provide energy for propulsion. ? We compared 15 polymers which are suitable to embed c-Si PV cells in to reduce PV modules’ weight. ? For comparison, we collected optical, mechanical and chemical properties for these polymers. ? Fluorides, silicones and GFR epoxy polymers show to be good candidates to embed c-Si PV cells in for PV boats.
Date : 18/01/2012 - Editeur : ScienceDirect
Impact of inverter configuration on energy cost of grid
En savoir plusPublication year: 2012 Source: Renewable Energy, Volume 41, May 2012, Pages 328-335 Fanbo He, Zhengming Zhao, Liqiang Yuan This paper proposes a method to evaluate and optimize inverter configurations for grid-connected PV systems. It is studied by Monte-Carlo analysis that how the inverter configuration and its operation strategy would impact on lifetime energy yield and the levelized cost of energy (LCOE) considering the PV array scale, environmental conditions, system cost, inverter efficiency and reliability. The efficiency characteristic of parallel inverters with a common DC bus is deliberated along with the optimal operation strategy. Inverter system performance ratio (ISPR) is proposed as an overall index of lifetime energy conversion efficiency. A case study is performed to demonstrate the proposed method. It shows that the configuration with a common DC bus is a potential solution to reduce the energy cost of PV power generation systems. As ancillary results, it is found that optimizing the PV panel orientation can improve the probability distribution of solar irradiance on the panel, and it is confirmed that an oversized PV array may help reduce the energy cost. Highlights ? Minimizing the energy cost is our final objective when designing PV systems. ? It is studied how inverter configurations impact on energy yield and energy cost. ? Environmental conditions, inverter system efficiency and reliability are considered. ? The configuration with a common DC bus has potential to lower the energy cost. ? The system efficiency and cost should be compromised from the system point of view.
Date : 18/01/2012 - Editeur : ScienceDirect
Effects of different acceptors in phenothiazine
En savoir plusPublication year: 2012 Source: Dyes and Pigments, Volume 94, Issue 1, July 2012, Pages 150-155 Zhongquan Wan, Chunyang Jia, Yandong Duan, Jiaqiang Zhang, Yuan Lin, ... In dye-sensitized solar cells (DSSCs), as the excited electrons from dye molecules are injected to the conduction band of semiconductor film through the acceptor moieties, the acceptor groups have significant influences on the photovoltaic properties of the dyes. In this paper, the effects of different acceptor groups (cyanoacetic acid and rhodanine-3-acetic acid) in two phenothiazine-triphenylamine dyes (PTZ-1andPTZ-2) on the optical, electrochemical properties and photovoltaic performances were studied. In comparison withPTZ-2, the photovoltaic performance ofPTZ-1is significantly improved by replacing rhodanine-3-acetic acid to cyanoacetic acid. The conversion efficiency of solar cell based on thePTZ-1is increased about 110%. The lower efficiency of solar cell based onPTZ-2is mainly because the delocalization of the excited state is broken between the 4-oxo-2-thioxothiazolidine ring and the acetic acid, which affects the electron injection fromPTZ-2to the conduction band of TiO2. Highlights ? The phenothiazine-triphenylamine organic dyes with different acceptors were studied. ? The absorption of PTZ-2 with rhodanine-3-acetic acid shows an obvious red shift. ? PTZ-1 gives effective and faster electron injection from the LUMO to TiO 2 electrode. ? PTZ-1 with cyanoacetic acid as acceptor shows the better photovoltaic performance.
Date : 18/01/2012 - Editeur : ScienceDirect
Novel D-p-A system based on zinc porphyrin dyes for dye
En savoir plusPublication year: 2012 Source: Dyes and Pigments, Volume 94, Issue 1, July 2012, Pages 143-149 Kang Deuk Seo, Myung Jun Lee, Hae Min Song, Hong Seok Kang, Hwan Kyu Kim We have designed and synthesized novel zinc porphyrin dyes which have a D-p-A system based on porphyrin derivatives containing a triphenylamine (TPA) electron-donating group and a phenyl carboxyl anchoring group substituted at the meso position of the porphyrin ring, yielding the push-pull porphyrins as the most efficient green dye for dye-sensitized solar cell (DSSC) applications. The synthesis and characterization of a novel D-p-A system based on zinc-porphyrin derivatives have been investigated through their photophysical and photoelectrochemical studies. A large red-shift of the absorption maxima due to introduction of the TPA moiety at the meso position of the porphyrin ring was expected in the D-p-A porphyrins, but the absorption maxima ofHKK-Pordyes were a little red-shifted in contrast to Zn[5,-10,15-triphenyl-20-(4-carboxylphenyl)-porphyrin], due to the tilted structure between TPA and the porphyrin unit. Under the photovoltaic performance measurement, the maximum incident photon-to-current conversion efficiency (IPCE) value of the DSSC based onHKK-Por 5was slightly higher than the efficiencies of the DSSCs based on otherHKK-Pordyes due to the introduction of the alkoxy group into the TPA moiety at the meso position of the porphyrin ring. A maximum photon-to-electron conversion efficiency of 3.36% was achieved with the DSSC based onHKK-Por 5dye (JSC = 9.04 mA/cm,VOC = 0.57 V, FF = 0.66) under AM1.5 irradiation (100 m Wcm). Highlights ? Novel zinc porphyrin dyes with triphenylamine moieties was synthesized for DSSC. ? Hexyloxy-containing TPA moiety was introduced at the 15 position of the porphyrin. ? It increases the electron-donating ability of D-p-A system based on porphyrin dye. ? It also decreases the dye aggregation. ? A conversion efficiency of 3.36% was achieved with the DSSC based on HKK-Por 5 dye.
Date : 18/01/2012 - Editeur : ScienceDirect
Photovoltaic performance of solid-state DSSCs sensitized with organic isophorone dyes: Effect of dye
En savoir plusPublication year: 2012 Source: Dyes and Pigments, Volume 94, Issue 1, July 2012, Pages 23-27 Bo Liu, Xiaoyan Li, Miaoyin Liu, Zhijun Ning, Qiong Zhang, ... Two isophorone sensitizers (S4andD-3) were utilized in solid-state dye-sensitized solar cells (DSSCs) usingspiro-OMeTAD as hole-transporting material. The dye-loaded amount ofD-3was almost 1.5 times as that ofS4which lead to higher light harvesting efficiency thanS4. Moreover, the larger dipole moment along the direction forD-3could cause more negative charges located close to the TiO2surface than that ofS4, resulting in a larger conduction band (CB) upshift of TiO2forD-3which was beneficial to an increase ofVoc. Promising results sensitized byD-3in solid-state DSSCs were achieved with a short-circuit photocurrent density (Jsc)of 3.4 mA cm, an open-circuit photovoltage (Voc) of 760 mV, a fill factor (FF) of 0.71, and an overall efficiency (?) of 1.92% while ruthenium dyeN3produced a?of 2.55% under the same conditions (AM 1.5, 100 mW cm). Highlights ? Two isophorone sensitizers were utilized in solid-state DSSCs. ? The donor indoline unit can exhibit better absorption performance with respect to triphenylamine unit. ? The more favorable dipole moment and adsorption form of D-3 leads to a larger CB upshift in energy level. ? The performances sensitized with D-3 in solid-state DSSCs were achieved with an overall efficiency ? of 1.92%.
Date : 18/01/2012 - Editeur : ScienceDirect
Al
En savoir plusPublication year: 2012 Source: Current Applied Physics, Volume 12, Issue 2, March 2012, Pages 380-384 K. Nagamani, N. Revathi, P. Prathap, Y. Lingappa, K.T. Ramakrishna Reddy ZnS is one of the potential candidates as a window/buffer layer for solar photovoltaic applications. Al-doped ZnS nanocrystalline films were grown by a simple and economic process, chemical solution growth method. The layers were prepared for different Al-dopant concentrations that vary in the range, 0–10 at. %. The effect of Al-doping on the composition, structure, optical, electrical and photoluminescence properties of the synthesized layers was determined using appropriate techniques. The elemental composition of a typical sample with 6 at. % ‘Al’ in ZnS was Zn = 44.9 at. %,S = 49.8 at. % and Al = 5.3 at. %. The films were nanocrystalline in nature and showed (111) plane of ZnS as the preferred orientation for all the doping concentrations. The layers with 6 at. % of Al showed a crystallite size of ~9 nm. The FTIR studies confirmed the presence of ZnS in the layers. The layers showed an average transmittance of ~75% in the visible region. The change of photoluminescence behaviour with dopant concentration was also studied. The electrical resistivity was considerably decreased from 10 Ocm to 10 Ocm with Al-doping. The detailed analysis of results will be presented and discussed. Highlights ? Deposition of ZnS:Al films by solution growth method varying Al-doping content. ? Investigation of the physical and chemical properties of annealed ZnS:Al layers. ? Study of photoluminescence in ZnS:Al layers to identify the defect states. ? Formation of ZnS:Al films with low electrical resistivity for solar cell application.
Date : 18/01/2012 - Editeur : ScienceDirect
