The optical window of low-observable platform needs to be compatible with ultra-broadband absorption,hence an optically-transparent absorber with ultra-broadband absorption is designed and analyzed in this paper.The t...The optical window of low-observable platform needs to be compatible with ultra-broadband absorption,hence an optically-transparent absorber with ultra-broadband absorption is designed and analyzed in this paper.The transparent materials indium-tin-oxide(ITO)film and polymethylmethacrylate(PMMA)are selected as the lossy layer and the supporting dielectric layer,respectively.The optically-transparent ultra-broadband absorber(OT-UBA)is composed of three layers of ITO square patterns,three layers of PMMA dielectric and a uniform ITO plane.The ITO square patterns can realize arbitrary equivalent series of RC(resistor and capacitor)circuit,so that three layers of ITO square patterns together with the ITO plane can achieve ultra-broadband absorption based on the equivalent circuit optimization.Measured results shows that the 90%-absorption bandwidth covers 2-17 GHz while the light transmittance achieves 59.6%with a total thickness of only 12.9 mm.展开更多
A broadband and ultra-thin absorber for solar cell application is designed. The absorber consists of three layers, and the difference is that the four split ring resonators made of metal gold are encrusted in the gall...A broadband and ultra-thin absorber for solar cell application is designed. The absorber consists of three layers, and the difference is that the four split ring resonators made of metal gold are encrusted in the gallium arsenide (GaAs) plane in the top layer. The simulated results show that a perfect absorption in the region from 481.2 to 684.0THz can be obtained for either transverse electric or magnetic polarization wave due to the coupling effect between the material of GaAs and gold. The metamaterial is ultra-thin, having the total thickness of 56nm, which is less than one-tenth resonance wavelength, and the absorption coefficients at the three resonance wavelengths are above 90%. Moreover, the effective medium theory, electric field and surface current distributions are adopted to explain the physical mechanism of the absorption, and the permittivity sensing applications are also discussed. As a result, the proposed structure can be used in many areas, such as solar cell, sensors, and integrated photodetectors.展开更多
The development of kesterite photovoltaic solar cells has been hindered by large open-circuit voltage(V_(oc))deficit.Recently,Snzn deep point defect and associative defect cluster have been recognized as the main culp...The development of kesterite photovoltaic solar cells has been hindered by large open-circuit voltage(V_(oc))deficit.Recently,Snzn deep point defect and associative defect cluster have been recognized as the main culprit for the Voc losses.Therefore,manipulating the deep-level donor of Snzn antisite defects is crucial for breaking through the bottleneck of present Cu_(2) ZnSn(S,Se)_(4)(CZTSSe)photovoltaic technology.In this study,the Snzn deep traps in CZTSSe absorber layer are suppressed by incorporation of Ge.The energy levels and concentration of Snzn defects measured by deep-level transient spectroscopy(DLTS)decrease significantly.In addition,the grain growth of CZTSSe films is also promoted due to Ge implantation,yielding the high quality absorber layer.Consequently,the efficiency of CZTSSe solar cells increases from 9.15%to 11.48%,largely attributed to the 41 mV Voc increment.展开更多
In this work, we have selected three number of stepped type solar stills of the same overall dimensions 620 mm (W) × 808 mm (L) but with different absorber surface areas due to the variation in the shape of the b...In this work, we have selected three number of stepped type solar stills of the same overall dimensions 620 mm (W) × 808 mm (L) but with different absorber surface areas due to the variation in the shape of the basin surface. The other design parameters like depth of water, thickness of glass cover, insulation thickness, type of condensing cover, absorbing material provided over the basin, and angle of inclination of the still were kept constant to study the effect of shape of the absorber surface over the distillate yield obtained. The shape of the absorber surface provided in the basins of solar stills A, E and F was flat, convex and concave respectively. When the convex and concave type stepped solar stills are used, the average daily water production has been found to be 56.60% and 29.24% higher than that of flat type stepped solar still respectively. Also an economic analysis was made. The payback period of flat type, convex type and concave type stepped solar still is 823 days, 525 days and 637 days respectively. Thus, the convex type solar still gives the returns within the least possible time as compared to other two types of stepped solar stills. The laboratory tests were conducted to test the quality of water after distillation. The tests indicate that the quality of water in terms of pH, electrical conductivity, total hardness, TDS, Alkalinity, Nitrates etc. is well within the desirable limits as prescribed by WHO for Indian specific conditions.展开更多
We propose an ultra-broadband and polarization independent planar absorber comprising multilayered graphene. The bandwidth of the proposed absorber is extended by increasing the number of layers of graphene, and it is...We propose an ultra-broadband and polarization independent planar absorber comprising multilayered graphene. The bandwidth of the proposed absorber is extended by increasing the number of layers of graphene, and it is polarization independent due to its symmetrical unit structure. The full wave simulation results show that an absorber with three graphenebased layers can efficiently harvest an electromagnetic wave with random polarization from 17.9 GHz to 188.7 GHz(i.e.,covering frequency regimes from K to D bands and relative bandwidth of - 165%). The physical absorption mechanism of ultra-broadband absorption has been elaborated upon using the destructive interference method and multiple resonances approach in a multilayered medium. The proposed absorber can be used in many applications such as medical treatment,electromagnetic compatibility, and stealth technique.展开更多
Copper zinc tin sulfide(CZTS)thin film was synthesized on soda lime glass substrate by using spin coating method.The synthesized CZTS thin film showed maximum absorption coefficient of 0.193×104 cm-1 and maximum ...Copper zinc tin sulfide(CZTS)thin film was synthesized on soda lime glass substrate by using spin coating method.The synthesized CZTS thin film showed maximum absorption coefficient of 0.193×104 cm-1 and maximum extinction coefficient of 0.011.The direct optical band gap,Urbach energy and steepness parameter of the synthesized CZTS thin film were 1.52 eV,0.52 eV and 0.05 respectively.The CZTS thin film was found to be polycrystalline tetragonal in nature.The scanning electron microscopy(SEM)revealed that the texture structure was formed for the CZTS thin film.展开更多
TiAIN solar selective absorbing coatings which were deposited on 304L stainless steel using cathodic arc evaporation method were annealed under non-vacuum at different temperatures with different times. The optical pr...TiAIN solar selective absorbing coatings which were deposited on 304L stainless steel using cathodic arc evaporation method were annealed under non-vacuum at different temperatures with different times. The optical properties (absorptance and emittance) of the coatings were measured by a spectrophotometer. It was found that, after being annealed for 2 hours at different temperatures, the absorptance of the coatings reached the highest value of 0.92 at 700 ℃ while the emittance got the lowest value of 0.38 at 800 ℃. When the coatings were annealed at 600 ℃ for 24 hours, the optical properties changed to 0.92/0.44 (absorptance/ emittance). By measuring the structure, morphology, elements and surface roughness of the coatings, it was found that both the elemental composition and the surface roughness of the coatings changed as a result of annealing, and these changes caused the change of the optical properties of the coatings.展开更多
In this study, effects of different nanoparticles and porosity of absorber tube on the performance of a Concentrating Parabolic Solar Collector(CPSC) were investigated. A section of porous-filled absorber tube was mod...In this study, effects of different nanoparticles and porosity of absorber tube on the performance of a Concentrating Parabolic Solar Collector(CPSC) were investigated. A section of porous-filled absorber tube was modeled as a semi-circular cavity under the solar radiation which is filled by nanofluids and the governing equations were solved by FlexPDE numerical software. The effect of four physical parameters, nanoparticles type, nanoparticles volume fraction(φ), Darcy number(Da) and Rayleigh number(Ra), on the Nusselt number(Nu) was discussed. It turns out that Cu nanoparticle is the most suitable one for such solar collectors, compared to the commonly used Fe_3O_4, Al_2O_3, TiO_2.With the increased addition of Cu nanoparticles all the parameters φ, Da and Ra shows a significant increase against the Nu, indicates the enhanced heat transfer in such cases. As a result, low concentration of Cu nanoparticle suspension combined with porous matrix was supposed to be beneficial for the performance enhancement of concentrating parabolic solar collector.展开更多
We successfully fabricate p-type ZnO:N films by using rf magnetron sputtering and in situ annealing in O_(2) atmosphere.These p-type ZnO:N films can be used as p-type window materials for extremely thin absorber(ETA)s...We successfully fabricate p-type ZnO:N films by using rf magnetron sputtering and in situ annealing in O_(2) atmosphere.These p-type ZnO:N films can be used as p-type window materials for extremely thin absorber(ETA)solar cells composed of quartz glass/p-ZnO:N/i-ZnO/CdSe/i-ZnO/n-ZnO:Al.The short-circuit photocurrent density,open circuit voltage,fill factor and conversion efficiency of the ETA solar cells can be determined to be 8.549 mA/cm^(2),0.702 V,0.437 and 2.623%,respectively,through measurements of photovoltaic properties under illumination with a 100 mW/cm^(2) at air-mass(AM)1.5.展开更多
The broadband metamaterial perfect absorber has been extensively studied due to its excellent characteristics and promising application prospect.In this work a solar broadband metamaterial perfect absorber is proposed...The broadband metamaterial perfect absorber has been extensively studied due to its excellent characteristics and promising application prospect.In this work a solar broadband metamaterial perfect absorber is proposed based on the structure of the germanium(Ge)cone array and the indium arsenide(InAs)dielectric film on the gold(Au)substrate.The results show that the absorption covers the whole ultraviolet-visible and near-infrared range.For the case of A>99%,the absorption bandwidth reaches up to 1230 nm with a wavelength range varied from 200 nm to 1430 nm.The proposed absorber is able to absorb more than 98.7%of the solar energy in a solar spectrum from 200 nm to 3000 nm.The electromagnetic dipole resonance and the high-order modes of the Ge cone couple strongly to the incident optical field,which introduces a strong coupling with the solar radiation and produces an ultra-broadband absorption.The absorption spectrum can be feasibly manipulated via tuning the structural parameters,and the polarization insensitivity performance is particularly excellent.The proposed absorber can possess wide applications in active photoelectric effects,thermion modulators,and photoelectric detectors.展开更多
Sialon/SiC composites were synthesized in situ from SiC,α-Si_(3)N_(4),AlN,calcined bauxite,quartz and Y_(2)O_(3) via layered buried sintering at different temperatures (1 540-1 640 ℃).The results showed that the O’...Sialon/SiC composites were synthesized in situ from SiC,α-Si_(3)N_(4),AlN,calcined bauxite,quartz and Y_(2)O_(3) via layered buried sintering at different temperatures (1 540-1 640 ℃).The results showed that the O’-sialon/SiC sample with 60 wt% silicon carbide sintered at 1 600 ℃ exhibited excellent mechanical properties,with apparent porosity of 16.01%,bulk density of 2.06 g·cm^(-3),bending strength of 52.63 MPa,and thermal expansion coefficient of 5.83×10-6 ℃^(-1).The oxide film formed on the surface was linked closely to O’-sialon,so the oxide film was not easily broken.After 100 h oxidization,the sample surface was smoother and denser,with oxidation weight gain rate 23.6 mg/cm^(2) and oxidation rate constant 2.0 mg^(2)·cm^(-4)·h^(-1).Therefore,the sample had the excellent high-temperature oxidation resistance.It was confirmed that the in-situ sialon/SiC composites could be a promising candidate for solar absorber owing to its high-temperature oxidation resistance.展开更多
Lead-free tin perovskite solar cells(PSCs)have undergone rapid development in recent years and are regarded as a promising ecofriendly photovoltaic technology.However,a strategy to suppress charge recombination via a ...Lead-free tin perovskite solar cells(PSCs)have undergone rapid development in recent years and are regarded as a promising ecofriendly photovoltaic technology.However,a strategy to suppress charge recombination via a built-in electric field inside a tin perovskite crystal is still lacking.In the present study,a formamidinium tin iodide(FASnI;)perovskite absorber with a vertical Sn;gradient was fabricated using a Lewis base-assisted recrystallization method to enhance the built-in electric field and minimize the bulk recombination loss inside the tin perovskites.Depth-dependent X-ray photoelectron spectroscopy revealed that the Fermi level upshifts with an increase in Sn;content from the bottom to the top in this heterogeneous FASnI;film,which generates an additional electric field to prevent the trapping of photo-induced electrons and holes.Consequently,the Sn;-gradient FASnI;absorber exhibits a promising efficiency of 13.82%for inverted tin PSCs with an open-circuit voltage increase of 130 mV,and the optimized cell maintains over 13%efficiency after continuous operation under 1-sun illumination for 1,000 h.展开更多
Tin(Sn)-based perovskite solar cells(PSCs)have received increasing attention in the domain of photovoltaics due to their environmentally friendly nature.In this paper,numerical modeling and simulation of hole transpor...Tin(Sn)-based perovskite solar cells(PSCs)have received increasing attention in the domain of photovoltaics due to their environmentally friendly nature.In this paper,numerical modeling and simulation of hole transport material(HTM)-free PSC based on methyl ammonium tin triiodide(CH_(3) NH_(3) SnI_(3))was performed using a one-dimensional solar cell capacitance simulator(SCAPS-1D)software.The eff ect of perovskite thickness,interface defect density,temperature,and electron transport material(ETM)on the photovoltaic performance of the device was explored.Prior to optimization,the device demonstrated a power conversion effi ciency(PCE)of 8.35%,fi ll factor(FF)of 51.93%,short-circuit current density(J_(sc))of 26.36 mA/cm 2,and open circuit voltage(V_(oc))of 0.610 V.Changing the above parameters individually while keeping others constant,the obtained optimal absorber thickness was 1.0μm,the interface defect density was 1010 cm-2,the temperature was 290 K,and the TiO 2 thickness was 0.01μm.On simulating with the optimized data,the fi nal device gave a PCE of 11.03%,FF of 50.78%,J_(sc) of 29.93 mA/cm 2,and V_(oc) of 0.726 V.Comparing the optimized and unoptimized metric parameters,an improvement of~32.10%in PCE,~13.41%in J_(sc),and~19.02%in V_(oc) were obtained.Therefore,the results of this study are encouraging and can pave the path for developing highly effi cient PSCs that are cost-eff ective,eco-friendly,and comparable to state-of-the-art.展开更多
In the past tens of years,the power conversion efficiency of Cu(In,Ga)Se2(CIGS)has continuously improved and been one of the fastest growing photovoltaic technologies that can also help us achieve the goal of carbon e...In the past tens of years,the power conversion efficiency of Cu(In,Ga)Se2(CIGS)has continuously improved and been one of the fastest growing photovoltaic technologies that can also help us achieve the goal of carbon emissions reduction.Among several key advances,the alkali element post-deposition treatment(AlK PDT)is regarded as the most important finding in the last 10 years,which has led to the improvement of CIGS solar cell efficiency from 20.4%to 23.35%.A profound understanding of the influence of alkali element on the chemical and electrical properties of the CIGS absorber along with the underlying mechanisms is of great importance.In this review,we summarize the strategies of the alkali element doping in CIGS solar cell,the problems to be noted in the PDT process,the effects on the CdS buffer layer,the effects of different alkali elements on the structure and morphology of the CIGS absorber layer,and retrospect the progress in the CIGS solar cell with emphasis on the alkali element post deposition treatment.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61901492 and 61901493)Provincial Natural Science Foundation of Hunan(Grant No.2022JJ30665)。
文摘The optical window of low-observable platform needs to be compatible with ultra-broadband absorption,hence an optically-transparent absorber with ultra-broadband absorption is designed and analyzed in this paper.The transparent materials indium-tin-oxide(ITO)film and polymethylmethacrylate(PMMA)are selected as the lossy layer and the supporting dielectric layer,respectively.The optically-transparent ultra-broadband absorber(OT-UBA)is composed of three layers of ITO square patterns,three layers of PMMA dielectric and a uniform ITO plane.The ITO square patterns can realize arbitrary equivalent series of RC(resistor and capacitor)circuit,so that three layers of ITO square patterns together with the ITO plane can achieve ultra-broadband absorption based on the equivalent circuit optimization.Measured results shows that the 90%-absorption bandwidth covers 2-17 GHz while the light transmittance achieves 59.6%with a total thickness of only 12.9 mm.
基金Supported by the National Natural Science Foundation of China under Grant No 61275174the Research Fund for the Doctoral Program of Higher Education of China under Grant No 20100162110068
文摘A broadband and ultra-thin absorber for solar cell application is designed. The absorber consists of three layers, and the difference is that the four split ring resonators made of metal gold are encrusted in the gallium arsenide (GaAs) plane in the top layer. The simulated results show that a perfect absorption in the region from 481.2 to 684.0THz can be obtained for either transverse electric or magnetic polarization wave due to the coupling effect between the material of GaAs and gold. The metamaterial is ultra-thin, having the total thickness of 56nm, which is less than one-tenth resonance wavelength, and the absorption coefficients at the three resonance wavelengths are above 90%. Moreover, the effective medium theory, electric field and surface current distributions are adopted to explain the physical mechanism of the absorption, and the permittivity sensing applications are also discussed. As a result, the proposed structure can be used in many areas, such as solar cell, sensors, and integrated photodetectors.
基金financially supported by the National Natural Science Foundation of China(U1904192,62074052,52072327,61974173,61874159 and 51802081)the Key Science and Technology Research Project of Education Department of Henan Province(19A140003)+1 种基金the Key Science and Technology Program of Henan Province(192102210001)Zhongyuan Thousand Talents(Zhongyuan Scholars)Program of Henan Province(202101510004)。
文摘The development of kesterite photovoltaic solar cells has been hindered by large open-circuit voltage(V_(oc))deficit.Recently,Snzn deep point defect and associative defect cluster have been recognized as the main culprit for the Voc losses.Therefore,manipulating the deep-level donor of Snzn antisite defects is crucial for breaking through the bottleneck of present Cu_(2) ZnSn(S,Se)_(4)(CZTSSe)photovoltaic technology.In this study,the Snzn deep traps in CZTSSe absorber layer are suppressed by incorporation of Ge.The energy levels and concentration of Snzn defects measured by deep-level transient spectroscopy(DLTS)decrease significantly.In addition,the grain growth of CZTSSe films is also promoted due to Ge implantation,yielding the high quality absorber layer.Consequently,the efficiency of CZTSSe solar cells increases from 9.15%to 11.48%,largely attributed to the 41 mV Voc increment.
文摘In this work, we have selected three number of stepped type solar stills of the same overall dimensions 620 mm (W) × 808 mm (L) but with different absorber surface areas due to the variation in the shape of the basin surface. The other design parameters like depth of water, thickness of glass cover, insulation thickness, type of condensing cover, absorbing material provided over the basin, and angle of inclination of the still were kept constant to study the effect of shape of the absorber surface over the distillate yield obtained. The shape of the absorber surface provided in the basins of solar stills A, E and F was flat, convex and concave respectively. When the convex and concave type stepped solar stills are used, the average daily water production has been found to be 56.60% and 29.24% higher than that of flat type stepped solar still respectively. Also an economic analysis was made. The payback period of flat type, convex type and concave type stepped solar still is 823 days, 525 days and 637 days respectively. Thus, the convex type solar still gives the returns within the least possible time as compared to other two types of stepped solar stills. The laboratory tests were conducted to test the quality of water after distillation. The tests indicate that the quality of water in terms of pH, electrical conductivity, total hardness, TDS, Alkalinity, Nitrates etc. is well within the desirable limits as prescribed by WHO for Indian specific conditions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61661012,61461016,61361005,and 61561013)the Natural Science Foundation of Guangxi,China(Grant No.2017JJB160028)+1 种基金the Program for Innovation Research Team of Guilin University of Electronic Technology,Chinathe Dean Project of Guangxi Key Laboratory of Wireless Wideband Communication and Signal Processing,China
文摘We propose an ultra-broadband and polarization independent planar absorber comprising multilayered graphene. The bandwidth of the proposed absorber is extended by increasing the number of layers of graphene, and it is polarization independent due to its symmetrical unit structure. The full wave simulation results show that an absorber with three graphenebased layers can efficiently harvest an electromagnetic wave with random polarization from 17.9 GHz to 188.7 GHz(i.e.,covering frequency regimes from K to D bands and relative bandwidth of - 165%). The physical absorption mechanism of ultra-broadband absorption has been elaborated upon using the destructive interference method and multiple resonances approach in a multilayered medium. The proposed absorber can be used in many applications such as medical treatment,electromagnetic compatibility, and stealth technique.
文摘Copper zinc tin sulfide(CZTS)thin film was synthesized on soda lime glass substrate by using spin coating method.The synthesized CZTS thin film showed maximum absorption coefficient of 0.193×104 cm-1 and maximum extinction coefficient of 0.011.The direct optical band gap,Urbach energy and steepness parameter of the synthesized CZTS thin film were 1.52 eV,0.52 eV and 0.05 respectively.The CZTS thin film was found to be polycrystalline tetragonal in nature.The scanning electron microscopy(SEM)revealed that the texture structure was formed for the CZTS thin film.
基金Funded by the "863" Hi-Tech Project of China(No.2009AA05Z440)
文摘TiAIN solar selective absorbing coatings which were deposited on 304L stainless steel using cathodic arc evaporation method were annealed under non-vacuum at different temperatures with different times. The optical properties (absorptance and emittance) of the coatings were measured by a spectrophotometer. It was found that, after being annealed for 2 hours at different temperatures, the absorptance of the coatings reached the highest value of 0.92 at 700 ℃ while the emittance got the lowest value of 0.38 at 800 ℃. When the coatings were annealed at 600 ℃ for 24 hours, the optical properties changed to 0.92/0.44 (absorptance/ emittance). By measuring the structure, morphology, elements and surface roughness of the coatings, it was found that both the elemental composition and the surface roughness of the coatings changed as a result of annealing, and these changes caused the change of the optical properties of the coatings.
基金financial support of the National Natural Science Foundation of China (No.51422604,51776165)China Postdoctoral Science Foundation (No.2017M610638)
文摘In this study, effects of different nanoparticles and porosity of absorber tube on the performance of a Concentrating Parabolic Solar Collector(CPSC) were investigated. A section of porous-filled absorber tube was modeled as a semi-circular cavity under the solar radiation which is filled by nanofluids and the governing equations were solved by FlexPDE numerical software. The effect of four physical parameters, nanoparticles type, nanoparticles volume fraction(φ), Darcy number(Da) and Rayleigh number(Ra), on the Nusselt number(Nu) was discussed. It turns out that Cu nanoparticle is the most suitable one for such solar collectors, compared to the commonly used Fe_3O_4, Al_2O_3, TiO_2.With the increased addition of Cu nanoparticles all the parameters φ, Da and Ra shows a significant increase against the Nu, indicates the enhanced heat transfer in such cases. As a result, low concentration of Cu nanoparticle suspension combined with porous matrix was supposed to be beneficial for the performance enhancement of concentrating parabolic solar collector.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10804071,51072113Shanghai Rising-Star Program under Grant No 11QA1402700+3 种基金the Innovation Program of Shanghai Municipal Education Commission under Grant No 11YZ266the Natural Science Foundation of Shanghai under Grant No 09ZR1420500the Natural Science Foundation of Guangdong Province under Grant No S2012010010017the Leading Academic Discipline Project of Shanghai Municipal Education Commission under Grant No J51902,Shanghai Municipal Education Commission Project(No sdj08013).
文摘We successfully fabricate p-type ZnO:N films by using rf magnetron sputtering and in situ annealing in O_(2) atmosphere.These p-type ZnO:N films can be used as p-type window materials for extremely thin absorber(ETA)solar cells composed of quartz glass/p-ZnO:N/i-ZnO/CdSe/i-ZnO/n-ZnO:Al.The short-circuit photocurrent density,open circuit voltage,fill factor and conversion efficiency of the ETA solar cells can be determined to be 8.549 mA/cm^(2),0.702 V,0.437 and 2.623%,respectively,through measurements of photovoltaic properties under illumination with a 100 mW/cm^(2) at air-mass(AM)1.5.
基金Project supported by the Natural Science Foundation of Guangdong Province,China(Grant No.2018A030313854)the Science and Technology Program of Guangzhou City,China(Grant No.2019050001).
文摘The broadband metamaterial perfect absorber has been extensively studied due to its excellent characteristics and promising application prospect.In this work a solar broadband metamaterial perfect absorber is proposed based on the structure of the germanium(Ge)cone array and the indium arsenide(InAs)dielectric film on the gold(Au)substrate.The results show that the absorption covers the whole ultraviolet-visible and near-infrared range.For the case of A>99%,the absorption bandwidth reaches up to 1230 nm with a wavelength range varied from 200 nm to 1430 nm.The proposed absorber is able to absorb more than 98.7%of the solar energy in a solar spectrum from 200 nm to 3000 nm.The electromagnetic dipole resonance and the high-order modes of the Ge cone couple strongly to the incident optical field,which introduces a strong coupling with the solar radiation and produces an ultra-broadband absorption.The absorption spectrum can be feasibly manipulated via tuning the structural parameters,and the polarization insensitivity performance is particularly excellent.The proposed absorber can possess wide applications in active photoelectric effects,thermion modulators,and photoelectric detectors.
基金Funded by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2018YFB1501002)Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(No.XHD2020-001)。
文摘Sialon/SiC composites were synthesized in situ from SiC,α-Si_(3)N_(4),AlN,calcined bauxite,quartz and Y_(2)O_(3) via layered buried sintering at different temperatures (1 540-1 640 ℃).The results showed that the O’-sialon/SiC sample with 60 wt% silicon carbide sintered at 1 600 ℃ exhibited excellent mechanical properties,with apparent porosity of 16.01%,bulk density of 2.06 g·cm^(-3),bending strength of 52.63 MPa,and thermal expansion coefficient of 5.83×10-6 ℃^(-1).The oxide film formed on the surface was linked closely to O’-sialon,so the oxide film was not easily broken.After 100 h oxidization,the sample surface was smoother and denser,with oxidation weight gain rate 23.6 mg/cm^(2) and oxidation rate constant 2.0 mg^(2)·cm^(-4)·h^(-1).Therefore,the sample had the excellent high-temperature oxidation resistance.It was confirmed that the in-situ sialon/SiC composites could be a promising candidate for solar absorber owing to its high-temperature oxidation resistance.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11834011 and 12074245)The work performed at the University of Tokyo was supported by JSPS KAKENHI Grant Number 21H02040 and the New Energy and Industrial Technology Development Organization(NEDO)+1 种基金T.W.,G.T.,L.K.O.,and Y.B.Q.acknowledge the support from the Energy Materials and Surface Sciences Unit of the Okinawa Institute of Science and Technology Graduate University.We thank Mrs Miwako Furue and Dr.Haibin Wang at the University of Tokyo for the GIXRD and EDS measurementsOpen access funding provided by Shanghai Jiao Tong University
文摘Lead-free tin perovskite solar cells(PSCs)have undergone rapid development in recent years and are regarded as a promising ecofriendly photovoltaic technology.However,a strategy to suppress charge recombination via a built-in electric field inside a tin perovskite crystal is still lacking.In the present study,a formamidinium tin iodide(FASnI;)perovskite absorber with a vertical Sn;gradient was fabricated using a Lewis base-assisted recrystallization method to enhance the built-in electric field and minimize the bulk recombination loss inside the tin perovskites.Depth-dependent X-ray photoelectron spectroscopy revealed that the Fermi level upshifts with an increase in Sn;content from the bottom to the top in this heterogeneous FASnI;film,which generates an additional electric field to prevent the trapping of photo-induced electrons and holes.Consequently,the Sn;-gradient FASnI;absorber exhibits a promising efficiency of 13.82%for inverted tin PSCs with an open-circuit voltage increase of 130 mV,and the optimized cell maintains over 13%efficiency after continuous operation under 1-sun illumination for 1,000 h.
文摘Tin(Sn)-based perovskite solar cells(PSCs)have received increasing attention in the domain of photovoltaics due to their environmentally friendly nature.In this paper,numerical modeling and simulation of hole transport material(HTM)-free PSC based on methyl ammonium tin triiodide(CH_(3) NH_(3) SnI_(3))was performed using a one-dimensional solar cell capacitance simulator(SCAPS-1D)software.The eff ect of perovskite thickness,interface defect density,temperature,and electron transport material(ETM)on the photovoltaic performance of the device was explored.Prior to optimization,the device demonstrated a power conversion effi ciency(PCE)of 8.35%,fi ll factor(FF)of 51.93%,short-circuit current density(J_(sc))of 26.36 mA/cm 2,and open circuit voltage(V_(oc))of 0.610 V.Changing the above parameters individually while keeping others constant,the obtained optimal absorber thickness was 1.0μm,the interface defect density was 1010 cm-2,the temperature was 290 K,and the TiO 2 thickness was 0.01μm.On simulating with the optimized data,the fi nal device gave a PCE of 11.03%,FF of 50.78%,J_(sc) of 29.93 mA/cm 2,and V_(oc) of 0.726 V.Comparing the optimized and unoptimized metric parameters,an improvement of~32.10%in PCE,~13.41%in J_(sc),and~19.02%in V_(oc) were obtained.Therefore,the results of this study are encouraging and can pave the path for developing highly effi cient PSCs that are cost-eff ective,eco-friendly,and comparable to state-of-the-art.
基金supported by the National Key R&D Program of China Grant(no.2018YFB1500200)the National Natural Science Foundation of China under Grant(nos.61804159 and 52173243)+2 种基金the Natural Science Foundation of Guangdong Province,Guangzhou,China(no.2021A1515011409)Shenzhen&Hong Kong Joint Research Program(no.SGDX20201103095605015)SIAT-CUHK Joint Laboratory of Photovoltaic Solar Energy.
文摘In the past tens of years,the power conversion efficiency of Cu(In,Ga)Se2(CIGS)has continuously improved and been one of the fastest growing photovoltaic technologies that can also help us achieve the goal of carbon emissions reduction.Among several key advances,the alkali element post-deposition treatment(AlK PDT)is regarded as the most important finding in the last 10 years,which has led to the improvement of CIGS solar cell efficiency from 20.4%to 23.35%.A profound understanding of the influence of alkali element on the chemical and electrical properties of the CIGS absorber along with the underlying mechanisms is of great importance.In this review,we summarize the strategies of the alkali element doping in CIGS solar cell,the problems to be noted in the PDT process,the effects on the CdS buffer layer,the effects of different alkali elements on the structure and morphology of the CIGS absorber layer,and retrospect the progress in the CIGS solar cell with emphasis on the alkali element post deposition treatment.