最大功率点跟踪(maximum power point tracking,MPPT)是光伏系统保持高效运行的有效方法。在光伏阵列发生局部遮挡时,其功率-电压曲线会出现多峰现象,传统粒子群算法(particle swarm optimization,PSO)在此情况下进行MPPT容易陷入局部...最大功率点跟踪(maximum power point tracking,MPPT)是光伏系统保持高效运行的有效方法。在光伏阵列发生局部遮挡时,其功率-电压曲线会出现多峰现象,传统粒子群算法(particle swarm optimization,PSO)在此情况下进行MPPT容易陷入局部最优问题,导致收敛精度降低。为解决以上问题,提出了一种二阶振荡粒子群算法应用于最大功率点跟踪,并针对多峰函数特点进行优化。在对粒子种群初始化时采用分散定位逼近极值的方式增加粒子群的全局搜索能力,提出有效的终止策略防止系统反复波动。在MATLAB/Simulink平台进行仿真对比分析的结果表明:改进算法可有效提升MPPT控制的效率和动态品质。展开更多
ZnO nanorod arrays （NRs） were synthesized on the fluorine-doped SnO2 transparent conductive glass （FTO） by a simple chemical bath deposition （CBD） method combined with alkali-etched method in potassium hydroxide...ZnO nanorod arrays （NRs） were synthesized on the fluorine-doped SnO2 transparent conductive glass （FTO） by a simple chemical bath deposition （CBD） method combined with alkali-etched method in potassium hydroxide （KOH） solution. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and current-voltage （I-V） curve were used to characterize the structure, morphologies and optoelectronic properties. The results demonstrated that ZnO NRs had wurtzite structures, the morphologies and photovoltaic properties of ZnO NRs were closely related to the concentration of KOH and etching time, well-aligned and uniformly distributed ZnO NRs were obtained after etching with 0.1 mol/L KOH for 1 h. ZnO NRs treated by KOH had been proved to have superior photovoltaic properties compared with high density ZnO NRs. When using ZnO NRs etched with 0.1 mol/L KOH for 1 h as the anode of solar cell, the conversion efficiency, short circuit current and open circuit voltage, compared with the unetched ZnO NRs, increased by 0.71%, 2.79 mA and 0.03 V, respectively.展开更多
Ho^3＋-doped titanium dioxide（TiO2：Ho^3＋） downconversion（DC） nanowires were synthesized through a simple hydrothermal method followed by a subsequent calcination process after being immersed in Ho（NO3）3 aqueou...Ho^3＋-doped titanium dioxide（TiO2：Ho^3＋） downconversion（DC） nanowires were synthesized through a simple hydrothermal method followed by a subsequent calcination process after being immersed in Ho（NO3）3 aqueous solution. Moreover, TiO2：Ho^3＋ nanowires（HTNWs） were used as the photoanode in dye-sensitized solar cells（DSSCs） to investigate their photoelectric properties. Scanning electron microscopy（SEM） and X-ray diffraction（XRD） were used to characterize the morphology and structure of the material, respectively. The photofluorescence and ultraviolet-visible absorption spectra of HTNWs reveal a DC from the near and middle ultraviolet light to visible light which matches the strong absorbed region of the N719 dye. Compared with the pure TNW photoanode, HTNWs DC photoanodes show greater photovoltaic efficiency. The photovoltaic conversion efficiency（η） of the DSSCs with HTNWs photoanode doped with 4% Ho2O3（mass fraction） is two times that with pure TNW photoanode. This enhancement could be attributed to HTNWs which could extend the spectral response range of DSSCs to the near and middle ultraviolet region and increase the short-circuit current density（Jsc） of DSSCs, thus leading to the enhancement of photovoltaic conversion efficiency.展开更多
Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing...Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.展开更多
Colloidal semiconductor nanocrystals have been proven to be promising candidates for applications in low‐cost and high‐performance photovoltaics,bioimaging,and photocatalysis due to their novel size‐and shape‐depe...Colloidal semiconductor nanocrystals have been proven to be promising candidates for applications in low‐cost and high‐performance photovoltaics,bioimaging,and photocatalysis due to their novel size‐and shape‐dependent properties.Among the colloidal systems,I‐III‐VI semiconductor nanocrystals(NCs)have drawn much attention in the past few decades.Compared to binary NCs,ternary I‐III‐VI NCs not only exhibit low toxicity,but also a high performance similar to that of binary NCs.In this review,we mainly focus on the synthesis,properties,and applications of I‐III‐VI NCs.We summarize the major synthesis methods,analyze their photophysical and electronic properties,and highlight some of the latest applications of I‐III‐VI NCs in solar cells,light‐emitting diodes,bioimaging,and photocatalysis.Finally,based on the information reviewed,we highlight the existing problems and challenges.展开更多
Splitting water into hydrogen and oxygen by dye-sensitized photoelectrochemical cell(DSPEC)is a promising approach to solar fuels production.In this study,a series of pyridine derivatives as surface additives were mod...Splitting water into hydrogen and oxygen by dye-sensitized photoelectrochemical cell(DSPEC)is a promising approach to solar fuels production.In this study,a series of pyridine derivatives as surface additives were modified on a molecular chromophore and water oxidation catalyst co-loaded TiO_(2)photoanode,TiO_(2)|RuP,1(RuP=Ru(4,4′-(PO3H2)2-2,2′-bipyridine)(2,2′-bipyridine)2,1=Ru(bda)(L)2,(bda=2,2′-bipyridine-6,6′-dicarboxylate,L=10-(pyridin-4-yloxy)decyl)phosphonic acid).The addition of pyridine additives was found to result in up to 42%increase in photocurrent.Under simulated sun-light irradiation,TiO_(2)|RuP,1,P1(P1=4-Hydroxypyridine)produced a photocurrent density of 1 mA/cm2 at a bias of 0.4 V vs.NHE in acetate buffer.Moreover,the observed photocurrents are correlated with the electron-donating ability of the substituent groups on pyridine ring.Transient absorption measurements and electrochemical impedance spectroscopy revealed that surface-bound pyridine can effectively retard the back-electron transfer from the TiO_(2)conduction band to the oxidized dye,which is a major process responsible for energy loss in DSPECs.展开更多
An on-axis holographic zone plate or an off-axis holographic zone plate used for the silicon solar cell will have a solar energy conversion factor of 2. 5. And the combination of the two plates will have its conversio...An on-axis holographic zone plate or an off-axis holographic zone plate used for the silicon solar cell will have a solar energy conversion factor of 2. 5. And the combination of the two plates will have its conversion factor of 5. Especially for the use of silver halide photographic emulsion, the cost can be cut down dramatically.展开更多
The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obt...The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal （PV/T） collector show the potential of obtaining high total energy efficiency.展开更多
According to the design method of laser resonator cavity, we optimized the primary parameters of resonator and utilized LD arrays symmetrically pumping manner to implementing output of the high-brightness laser in our...According to the design method of laser resonator cavity, we optimized the primary parameters of resonator and utilized LD arrays symmetrically pumping manner to implementing output of the high-brightness laser in our laser cutter, then which was applied to precisely cutting the conductive film of CulnSe2 solar cells, the buried contact silicon solar cells＇ electrode groove, and perforating in wafer which is used to the emitter wrap through silicon solar cells. Laser processing precision was less than 40μm, the results have met solar cell＇s fabrication technology, and made fmally the buried cells＇ conversion efficiency be improved from 18% to 21%.展开更多
The performance of each type of building must meet all the needs and requests of new real estate markets. In fact, in the excellent architectures, the user can manage, with autonomy and flexibility, each system and pr...The performance of each type of building must meet all the needs and requests of new real estate markets. In fact, in the excellent architectures, the user can manage, with autonomy and flexibility, each system and product, according to the new energy and building technologies too. The main objective is the social and environmental sustainability with the reduction of fossil fuels and the greenhouse gas effect, pushing the use of renewable energies, in a new trend of land regeneration with sustainable buildings and settlement recovery. The energy crisis, mainly generated by the climate change, the air pollution, with consequent extinction of the species, reduction of the land and the work, the degradation and the environmental and seismic risk, focuses on the security and quality of construction systems, integrated use of clean resources. The methodologies aimed at integrating of energy-efficient and innovative building technologies in architecture, from design to management, to produce electric and thermal energy with active and passive properties, for a high-performance habitat. Therefore, the use of solar photovoltaic in the buildings, BIPV （Building Integrated Photovoltaic） with high-performance glass vision, efficient systems, intelligent materials, is integrated in architectures with the use of innovative construction systems, finally, technology of OPV （Organic Photovoltaic）, multi-junction cells, the dye sensitized solar cells in the solid state, etc., and adoption of storage systems.展开更多
In this study, the authors have shown the power conversion efficiency of flexible organic solar cells. The structure of the device is PET/ITO/PEDOT： PSS/P3HT： PCBM/AI. P3HT （poly-3-hexylthiophene）. It was used as ...In this study, the authors have shown the power conversion efficiency of flexible organic solar cells. The structure of the device is PET/ITO/PEDOT： PSS/P3HT： PCBM/AI. P3HT （poly-3-hexylthiophene）. It was used as an electron donor, PCBM （[6, 6]-phenyl C6 l-butyric acid methyl ester） as an electron acceptor and PEDOT： PSS used as a HIL （hole injection layer）. These materials were deposited by spin coating method on the flexible substrates. Photolithography method is used to etch ITO. The electrical parameters of the fabricated cells were investigated by means of J （V）, FF （fill factor）, the efficiency （r/）, photocurrent and IPCE measurement. It was observed that 45% of the absorbed photons are converted into current. The results obtained using etching technology by photolithography is better than that obtained in the clean room.展开更多
The accelerated life test was carded out to investigate the change of spectral transmittance of di-methyl silicon oil and the effects on the electrical performance of silicon solar cell. The di-methyl silicon oil samp...The accelerated life test was carded out to investigate the change of spectral transmittance of di-methyl silicon oil and the effects on the electrical performance of silicon solar cell. The di-methyl silicon oil samples be- fore and after accelerated life test were analyzed by FT-IR, GC-MS and LC-MS. The ring compounds and linear compounds with larger molecular weight were detected. The spectral transmittance of di-methyl silicon oil de- creased because the chromophore and auxochrome of the products made a sunlight receive decrease on the surface of the solar celt, and resulted in the reduction of cell performance. According to the decrease of spectral transmit- tance of di-methyl silicon oil, two recovery methods were proposed. The results showed that extraction was supe- rior to vacuum distillation in recovering the aged di-methyl silicon oil.展开更多
Inline characterization for fabrication of silicon wafer PV （photovoltaic） devices may be used to optimize device efficiencies, reduce their performance variance, and their cost of production. In this article, the f...Inline characterization for fabrication of silicon wafer PV （photovoltaic） devices may be used to optimize device efficiencies, reduce their performance variance, and their cost of production. In this article, the frozen in strain from a variety of extended defects in silicon is shown to effect the polarization of light transmitted through a silicon substrate due to the photo-elastic effect. Transmission polarimetry on pre-fabricated silicon substrates may be used for identification of extended defects in the materials using a polarization analysis instrument. Instrumentation is proposed for detection of defects in raw silicon wafers for applications like raw silicon wafer sorting, scanning silicon bricks, and inline inspection prior to solar cell metallization. Such analysis may assist with gettering of silicon solar cells, may be implemented in the sorting and rejection procedures in PV device fabrication, and in general shows advantages for detection of defects in silicon wafer solar cell materials and devices.展开更多
Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO...Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO_(4) electrodes was ascribed to the removal of MoO_(x) segregations,which are considered to be surface recombination centers for photoinduced electrons and holes.However,this proposed mechanism cannot explain why activated Mo‐doped BiVO_(4) electrodes gradually lose their activity when exposed to air.In this study,based on various characterizations,it is suggested that electrochemical treatment not only removes partial MoO_(x) segregations but also initiates the formation of H_(y)MoO_(x) surface defects,which provide charge transfer channels for photogenerated holes.The charge separation of the Mo‐doped BiVO_(4) electrode was significantly enhanced by these charge transfer channels.This study offers a new insight into the electrochemical activation of Mo‐doped BiVO_(4) photoanodes,and the new concept of surface charge transfer channels,a long overlooked factor,will be valuable for the development of other(photo)electrocatalytic systems.展开更多
In this paper, the modeling ofa bifacial polycrystalline silicon solar cells vertical junction is presented. The study in dynamic frequency is limited to wavelengths from 400 nm to 1100 nm. The dependence of solar cel...In this paper, the modeling ofa bifacial polycrystalline silicon solar cells vertical junction is presented. The study in dynamic frequency is limited to wavelengths from 400 nm to 1100 nm. The dependence of solar cell spectral response on wavelengths for several modulation frequencies was evaluated by using solar cell internal quantum efficiency.The objective is to characterize the polycrystalline silicon in 3D. The effect of frequency modulation pulsation on the phase of internal quantum efficiency was presented as well as values of shunt and series resistance for various grains size values. The results show that the value of maximum internal quantum efficiency is about 50% with a wavelength of 0,82 nm and a frequency of 103 rad/s under monochromatic illumination.展开更多
This research analyses the operation of a solar PV powered electric vehicle charging station with energy storage, that has been developed and demonstrated at the University of California--Davis, West Village, the larg...This research analyses the operation of a solar PV powered electric vehicle charging station with energy storage, that has been developed and demonstrated at the University of California--Davis, West Village, the largest planned zero-energy consumption community in the U.S. The intelligent energy management approach introduces solar PV electrical energy forecasting and EV （electric vehicle） charging demand projection to optimize the SOC （state of charge） of the buffer battery. The charging station has been operated continuously and routinely used by several EV users for a year. The actual operation shows that, a workplace charging station equipped with a buffer battery and with intelligent energy management can lower and reduce the station＇s peak power demand, and reduce the energy exchange with the utility grid by a factor of 2. The battery recharging power demand was shifted away from the on-peak time periods to the off-peak time periods, which will benefit the charging station owner from less energy use during peak periods when time-of-use rates are higher. The standard cell voltage deviation of the 220 cells was calculated to analyse the battery cell consistency during the resting, charging and discharging periods. The analysis shows that, the 220 50Ah cells show excellent voltage consistency with voltage deviation of less than 0.005 V within the battery SOC of 20%-80%. The voltage deviation doubles when the battery SOC reaches 90%. The comparison of cell voltage deviation at the beginning and after one year operation indicates that, the battery shows perfect cell voltage consistency and there is no obvious consistency deterioration during the battery resting, charging and discharging periods.展开更多
The laser equipment is one of the key equipment in the production line of the solar energy. In this article, the author de-scribes the application of the laser equipment in the production line of the amorphous silicon...The laser equipment is one of the key equipment in the production line of the solar energy. In this article, the author de-scribes the application of the laser equipment in the production line of the amorphous silicon film solar cells, and points out that the stable and exactitude is the key direction of the future development of the laser scribing equipment.展开更多
Due to their particular optical characteristics,metallic island films have the potential to significantly increase the energy conversion efficiency of solar cell.We experimentally and theoretically investigated the ef...Due to their particular optical characteristics,metallic island films have the potential to significantly increase the energy conversion efficiency of solar cell.We experimentally and theoretically investigated the effect of substrate temperature on the morphologies and optical properties of the silver island films.At low temperature,below 300 ℃,as the substrate temperature increases.Compared to the films prepared at room temperature,the sizes of nanoparticles decrease and the Absorption peaks shift to shorter wavelength accompanied by an increase density resulting in a 150% Absorption efficiency.As the substrate temperature goes up to 300 ℃,nanoparticles with larger in-plan(X-Y)dimensions are formed,the number density decreases and the Absorption peaks redshift but the Absorption efficiency is still 10% higher.Numerical simulation reveals that these behaviors are a consequence of morphologies transformation.展开更多
MXenes are emerging two-dimensional(2D)nanomaterials composed of transition metal carbides and/or nitrides and possess unique layered structures with abundant surface functional groups,which enable them with excellent...MXenes are emerging two-dimensional(2D)nanomaterials composed of transition metal carbides and/or nitrides and possess unique layered structures with abundant surface functional groups,which enable them with excellent and tunable properties.MXenes films can be solution-processed in polar solvents and are very suitable for optoelectronic device applications.Especially,Ti_(3)C_(2)T_(x) MXene with the clear advantages of facile synthesis,flexible surface controlling,easily tunable work function,high optical transmittance and excellent conductivity shows great potential for applications in organic/perovskite optoelectronic devices.Therefore,this review briefly introduces the mainstream synthesis methods,optical and electrical properties of MXenes,and comprehensively summarizes the versatile applications of Ti_(3)C_(2)T_(x) MXene in different functional layers(electrode,interface layer and active layer)of organic/perovskite optoelectronic devices including solar cells and light-emitting diodes.Finally,the current application characteristics and the future possibilities of MXenes in organic/perovskite optoelectronic devices are concluded and discussed.展开更多
This work highlights the design and the realization of an automatic solar-panel orientation system in order to achieve high-performances. The solar panel sensor constitutes the main part of the system, since it ensure...This work highlights the design and the realization of an automatic solar-panel orientation system in order to achieve high-performances. The solar panel sensor constitutes the main part of the system, since it ensures the pursuit of the sunbeam. The management of the system, depending on the movements, the presence of sun, and the regular checkup of the system evolution, is ensured by an electronic unit executed around a microcontroller.展开更多
文摘最大功率点跟踪(maximum power point tracking,MPPT)是光伏系统保持高效运行的有效方法。在光伏阵列发生局部遮挡时,其功率-电压曲线会出现多峰现象,传统粒子群算法(particle swarm optimization,PSO)在此情况下进行MPPT容易陷入局部最优问题,导致收敛精度降低。为解决以上问题,提出了一种二阶振荡粒子群算法应用于最大功率点跟踪,并针对多峰函数特点进行优化。在对粒子种群初始化时采用分散定位逼近极值的方式增加粒子群的全局搜索能力,提出有效的终止策略防止系统反复波动。在MATLAB/Simulink平台进行仿真对比分析的结果表明:改进算法可有效提升MPPT控制的效率和动态品质。
基金Project (21171027) supported by the National Natural Science Foundation of ChinaProject (K1001020-11) supported by the Science and Technology Key Project of Changsha City, ChinaProject ([2010]70) supported by Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, China
文摘ZnO nanorod arrays （NRs） were synthesized on the fluorine-doped SnO2 transparent conductive glass （FTO） by a simple chemical bath deposition （CBD） method combined with alkali-etched method in potassium hydroxide （KOH） solution. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and current-voltage （I-V） curve were used to characterize the structure, morphologies and optoelectronic properties. The results demonstrated that ZnO NRs had wurtzite structures, the morphologies and photovoltaic properties of ZnO NRs were closely related to the concentration of KOH and etching time, well-aligned and uniformly distributed ZnO NRs were obtained after etching with 0.1 mol/L KOH for 1 h. ZnO NRs treated by KOH had been proved to have superior photovoltaic properties compared with high density ZnO NRs. When using ZnO NRs etched with 0.1 mol/L KOH for 1 h as the anode of solar cell, the conversion efficiency, short circuit current and open circuit voltage, compared with the unetched ZnO NRs, increased by 0.71%, 2.79 mA and 0.03 V, respectively.
基金Project(2012FU125X03)supported by Open Research Fund Project of National Engineering Research Center of SeafoodChina+3 种基金Project(2011–191)supported by the Key Science and Technology Platform of Liaoning Provincial Education DepartmentChinaProject(2010–354)supported by the Science and Technology Platform of DalianChina
文摘Ho^3＋-doped titanium dioxide（TiO2：Ho^3＋） downconversion（DC） nanowires were synthesized through a simple hydrothermal method followed by a subsequent calcination process after being immersed in Ho（NO3）3 aqueous solution. Moreover, TiO2：Ho^3＋ nanowires（HTNWs） were used as the photoanode in dye-sensitized solar cells（DSSCs） to investigate their photoelectric properties. Scanning electron microscopy（SEM） and X-ray diffraction（XRD） were used to characterize the morphology and structure of the material, respectively. The photofluorescence and ultraviolet-visible absorption spectra of HTNWs reveal a DC from the near and middle ultraviolet light to visible light which matches the strong absorbed region of the N719 dye. Compared with the pure TNW photoanode, HTNWs DC photoanodes show greater photovoltaic efficiency. The photovoltaic conversion efficiency（η） of the DSSCs with HTNWs photoanode doped with 4% Ho2O3（mass fraction） is two times that with pure TNW photoanode. This enhancement could be attributed to HTNWs which could extend the spectral response range of DSSCs to the near and middle ultraviolet region and increase the short-circuit current density（Jsc） of DSSCs, thus leading to the enhancement of photovoltaic conversion efficiency.
文摘Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.
文摘Colloidal semiconductor nanocrystals have been proven to be promising candidates for applications in low‐cost and high‐performance photovoltaics,bioimaging,and photocatalysis due to their novel size‐and shape‐dependent properties.Among the colloidal systems,I‐III‐VI semiconductor nanocrystals(NCs)have drawn much attention in the past few decades.Compared to binary NCs,ternary I‐III‐VI NCs not only exhibit low toxicity,but also a high performance similar to that of binary NCs.In this review,we mainly focus on the synthesis,properties,and applications of I‐III‐VI NCs.We summarize the major synthesis methods,analyze their photophysical and electronic properties,and highlight some of the latest applications of I‐III‐VI NCs in solar cells,light‐emitting diodes,bioimaging,and photocatalysis.Finally,based on the information reviewed,we highlight the existing problems and challenges.
文摘Splitting water into hydrogen and oxygen by dye-sensitized photoelectrochemical cell(DSPEC)is a promising approach to solar fuels production.In this study,a series of pyridine derivatives as surface additives were modified on a molecular chromophore and water oxidation catalyst co-loaded TiO_(2)photoanode,TiO_(2)|RuP,1(RuP=Ru(4,4′-(PO3H2)2-2,2′-bipyridine)(2,2′-bipyridine)2,1=Ru(bda)(L)2,(bda=2,2′-bipyridine-6,6′-dicarboxylate,L=10-(pyridin-4-yloxy)decyl)phosphonic acid).The addition of pyridine additives was found to result in up to 42%increase in photocurrent.Under simulated sun-light irradiation,TiO_(2)|RuP,1,P1(P1=4-Hydroxypyridine)produced a photocurrent density of 1 mA/cm2 at a bias of 0.4 V vs.NHE in acetate buffer.Moreover,the observed photocurrents are correlated with the electron-donating ability of the substituent groups on pyridine ring.Transient absorption measurements and electrochemical impedance spectroscopy revealed that surface-bound pyridine can effectively retard the back-electron transfer from the TiO_(2)conduction band to the oxidized dye,which is a major process responsible for energy loss in DSPECs.
文摘An on-axis holographic zone plate or an off-axis holographic zone plate used for the silicon solar cell will have a solar energy conversion factor of 2. 5. And the combination of the two plates will have its conversion factor of 5. Especially for the use of silver halide photographic emulsion, the cost can be cut down dramatically.
文摘The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal （PV/T） collector show the potential of obtaining high total energy efficiency.
基金This work was supported by the Student’s Innovating Foundationin Nankai University.
文摘According to the design method of laser resonator cavity, we optimized the primary parameters of resonator and utilized LD arrays symmetrically pumping manner to implementing output of the high-brightness laser in our laser cutter, then which was applied to precisely cutting the conductive film of CulnSe2 solar cells, the buried contact silicon solar cells＇ electrode groove, and perforating in wafer which is used to the emitter wrap through silicon solar cells. Laser processing precision was less than 40μm, the results have met solar cell＇s fabrication technology, and made fmally the buried cells＇ conversion efficiency be improved from 18% to 21%.
文摘The performance of each type of building must meet all the needs and requests of new real estate markets. In fact, in the excellent architectures, the user can manage, with autonomy and flexibility, each system and product, according to the new energy and building technologies too. The main objective is the social and environmental sustainability with the reduction of fossil fuels and the greenhouse gas effect, pushing the use of renewable energies, in a new trend of land regeneration with sustainable buildings and settlement recovery. The energy crisis, mainly generated by the climate change, the air pollution, with consequent extinction of the species, reduction of the land and the work, the degradation and the environmental and seismic risk, focuses on the security and quality of construction systems, integrated use of clean resources. The methodologies aimed at integrating of energy-efficient and innovative building technologies in architecture, from design to management, to produce electric and thermal energy with active and passive properties, for a high-performance habitat. Therefore, the use of solar photovoltaic in the buildings, BIPV （Building Integrated Photovoltaic） with high-performance glass vision, efficient systems, intelligent materials, is integrated in architectures with the use of innovative construction systems, finally, technology of OPV （Organic Photovoltaic）, multi-junction cells, the dye sensitized solar cells in the solid state, etc., and adoption of storage systems.
文摘In this study, the authors have shown the power conversion efficiency of flexible organic solar cells. The structure of the device is PET/ITO/PEDOT： PSS/P3HT： PCBM/AI. P3HT （poly-3-hexylthiophene）. It was used as an electron donor, PCBM （[6, 6]-phenyl C6 l-butyric acid methyl ester） as an electron acceptor and PEDOT： PSS used as a HIL （hole injection layer）. These materials were deposited by spin coating method on the flexible substrates. Photolithography method is used to etch ITO. The electrical parameters of the fabricated cells were investigated by means of J （V）, FF （fill factor）, the efficiency （r/）, photocurrent and IPCE measurement. It was observed that 45% of the absorbed photons are converted into current. The results obtained using etching technology by photolithography is better than that obtained in the clean room.
基金Supported by the National Natural Science Foundation of China(No.51478297)Program of Introducing Talents of Discipline(No.B13011)
文摘The accelerated life test was carded out to investigate the change of spectral transmittance of di-methyl silicon oil and the effects on the electrical performance of silicon solar cell. The di-methyl silicon oil samples be- fore and after accelerated life test were analyzed by FT-IR, GC-MS and LC-MS. The ring compounds and linear compounds with larger molecular weight were detected. The spectral transmittance of di-methyl silicon oil de- creased because the chromophore and auxochrome of the products made a sunlight receive decrease on the surface of the solar celt, and resulted in the reduction of cell performance. According to the decrease of spectral transmit- tance of di-methyl silicon oil, two recovery methods were proposed. The results showed that extraction was supe- rior to vacuum distillation in recovering the aged di-methyl silicon oil.
文摘Inline characterization for fabrication of silicon wafer PV （photovoltaic） devices may be used to optimize device efficiencies, reduce their performance variance, and their cost of production. In this article, the frozen in strain from a variety of extended defects in silicon is shown to effect the polarization of light transmitted through a silicon substrate due to the photo-elastic effect. Transmission polarimetry on pre-fabricated silicon substrates may be used for identification of extended defects in the materials using a polarization analysis instrument. Instrumentation is proposed for detection of defects in raw silicon wafers for applications like raw silicon wafer sorting, scanning silicon bricks, and inline inspection prior to solar cell metallization. Such analysis may assist with gettering of silicon solar cells, may be implemented in the sorting and rejection procedures in PV device fabrication, and in general shows advantages for detection of defects in silicon wafer solar cell materials and devices.
文摘Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO_(4) electrodes was ascribed to the removal of MoO_(x) segregations,which are considered to be surface recombination centers for photoinduced electrons and holes.However,this proposed mechanism cannot explain why activated Mo‐doped BiVO_(4) electrodes gradually lose their activity when exposed to air.In this study,based on various characterizations,it is suggested that electrochemical treatment not only removes partial MoO_(x) segregations but also initiates the formation of H_(y)MoO_(x) surface defects,which provide charge transfer channels for photogenerated holes.The charge separation of the Mo‐doped BiVO_(4) electrode was significantly enhanced by these charge transfer channels.This study offers a new insight into the electrochemical activation of Mo‐doped BiVO_(4) photoanodes,and the new concept of surface charge transfer channels,a long overlooked factor,will be valuable for the development of other(photo)electrocatalytic systems.
文摘In this paper, the modeling ofa bifacial polycrystalline silicon solar cells vertical junction is presented. The study in dynamic frequency is limited to wavelengths from 400 nm to 1100 nm. The dependence of solar cell spectral response on wavelengths for several modulation frequencies was evaluated by using solar cell internal quantum efficiency.The objective is to characterize the polycrystalline silicon in 3D. The effect of frequency modulation pulsation on the phase of internal quantum efficiency was presented as well as values of shunt and series resistance for various grains size values. The results show that the value of maximum internal quantum efficiency is about 50% with a wavelength of 0,82 nm and a frequency of 103 rad/s under monochromatic illumination.
文摘This research analyses the operation of a solar PV powered electric vehicle charging station with energy storage, that has been developed and demonstrated at the University of California--Davis, West Village, the largest planned zero-energy consumption community in the U.S. The intelligent energy management approach introduces solar PV electrical energy forecasting and EV （electric vehicle） charging demand projection to optimize the SOC （state of charge） of the buffer battery. The charging station has been operated continuously and routinely used by several EV users for a year. The actual operation shows that, a workplace charging station equipped with a buffer battery and with intelligent energy management can lower and reduce the station＇s peak power demand, and reduce the energy exchange with the utility grid by a factor of 2. The battery recharging power demand was shifted away from the on-peak time periods to the off-peak time periods, which will benefit the charging station owner from less energy use during peak periods when time-of-use rates are higher. The standard cell voltage deviation of the 220 cells was calculated to analyse the battery cell consistency during the resting, charging and discharging periods. The analysis shows that, the 220 50Ah cells show excellent voltage consistency with voltage deviation of less than 0.005 V within the battery SOC of 20%-80%. The voltage deviation doubles when the battery SOC reaches 90%. The comparison of cell voltage deviation at the beginning and after one year operation indicates that, the battery shows perfect cell voltage consistency and there is no obvious consistency deterioration during the battery resting, charging and discharging periods.
文摘The laser equipment is one of the key equipment in the production line of the solar energy. In this article, the author de-scribes the application of the laser equipment in the production line of the amorphous silicon film solar cells, and points out that the stable and exactitude is the key direction of the future development of the laser scribing equipment.
基金The Distinguished Youth Foundation of Hunan Province(03JJY1008)The Natural Science Foundation of Hunan Province(06JJ2034)
文摘Due to their particular optical characteristics,metallic island films have the potential to significantly increase the energy conversion efficiency of solar cell.We experimentally and theoretically investigated the effect of substrate temperature on the morphologies and optical properties of the silver island films.At low temperature,below 300 ℃,as the substrate temperature increases.Compared to the films prepared at room temperature,the sizes of nanoparticles decrease and the Absorption peaks shift to shorter wavelength accompanied by an increase density resulting in a 150% Absorption efficiency.As the substrate temperature goes up to 300 ℃,nanoparticles with larger in-plan(X-Y)dimensions are formed,the number density decreases and the Absorption peaks redshift but the Absorption efficiency is still 10% higher.Numerical simulation reveals that these behaviors are a consequence of morphologies transformation.
基金Projects(52063010,51961010)supported by the National Natural Science Foundation of China。
文摘MXenes are emerging two-dimensional(2D)nanomaterials composed of transition metal carbides and/or nitrides and possess unique layered structures with abundant surface functional groups,which enable them with excellent and tunable properties.MXenes films can be solution-processed in polar solvents and are very suitable for optoelectronic device applications.Especially,Ti_(3)C_(2)T_(x) MXene with the clear advantages of facile synthesis,flexible surface controlling,easily tunable work function,high optical transmittance and excellent conductivity shows great potential for applications in organic/perovskite optoelectronic devices.Therefore,this review briefly introduces the mainstream synthesis methods,optical and electrical properties of MXenes,and comprehensively summarizes the versatile applications of Ti_(3)C_(2)T_(x) MXene in different functional layers(electrode,interface layer and active layer)of organic/perovskite optoelectronic devices including solar cells and light-emitting diodes.Finally,the current application characteristics and the future possibilities of MXenes in organic/perovskite optoelectronic devices are concluded and discussed.
文摘This work highlights the design and the realization of an automatic solar-panel orientation system in order to achieve high-performances. The solar panel sensor constitutes the main part of the system, since it ensures the pursuit of the sunbeam. The management of the system, depending on the movements, the presence of sun, and the regular checkup of the system evolution, is ensured by an electronic unit executed around a microcontroller.
