In this work,a Cu_(2)ZnSnS_(4)(CZTS)ingot is grown via a melting method,then cooled;the resulting molten stoichiomet-ric mixture is sealed off in a quartz ampoule under vacuum.The CZTS powder chemical composition anal...In this work,a Cu_(2)ZnSnS_(4)(CZTS)ingot is grown via a melting method,then cooled;the resulting molten stoichiomet-ric mixture is sealed off in a quartz ampoule under vacuum.The CZTS powder chemical composition analyses are determined us-ing energy dispersive spectroscopy,and revealing the slightly Cu-rich and Zn-poor character of the ingot.Powder X-ray diffrac-tion analysis reveals a crystalline structure with a kesterite phase formation,and a preferred orientation of(112)plane.The lat-tice constants of the a-and c-axes,calculated based on the XRD analyses,are a=5.40Åand c=10.84Å.Based on Hall measure-ments at room temperature,we find that the crystal exhibits p-type conductivity,with a high concentration of 1018 cm^(-3),a res-istivity of 1.7Ωcm,and a mobility of 10.69 cm^(2)V-1s-1.Activation energies are estimated based on an Arrhenius plot of conductiv-ity versus 1/T,for a temperature range of 80-350 K,measuring 35 and 160 meV in low-and high-temperature regimes,respect-ively,which is attributed to complex defects(2CuZn+SnZn)and antisite defects(CuZn),respectively.The observed scattering mech-anisms are attributed to ionized impurities and acoustic phonons at low and high temperatures,respectively.The extracted band-gap is 1.37 eV.展开更多
Cu2ZnSnS4 (CZTS) thin films were successfully fabricated on glass substrates by sulfurizing Cu-Sn-Zn multilayer precursors, which were deposited by ion beam sputtering and RF magnetron sputtering, respectively. The st...Cu2ZnSnS4 (CZTS) thin films were successfully fabricated on glass substrates by sulfurizing Cu-Sn-Zn multilayer precursors, which were deposited by ion beam sputtering and RF magnetron sputtering, respectively. The structural, electrical and optical properties of the prepared films under various processing conditions were investigated in detail. Results showed that the as-deposited CZTS thin films with the precursors by both ion beam sputtering and RF magnetron sputtering have a composition near stoichiometric. The crystallization of the samples, however, has a strong dependence on the atomic percent of constituents of the prepared CZTS films. A single phase stannite-type structure CZTS with a large absorption coefficient of 104/cm in the visible range could be obtained after sulfurization at 520℃ for 2 h. The samples relative to the RF magnetron sputtering showed a low resistivity of 0.073 ?cm and band gap energy of about 1.53 eV. The samples relative to the ion beam sputtering exhibited a resistivity of 0.36 Ωcm and the band gap energy is about 1.51 eV.展开更多
Inexpensive,safe,and efficient conversion of solar energy to hydrogen from water splitting requires the development of effective and durable photocatalysts.Cu_(2)ZnSnS_(4)(CZTS),the emerging quaternary chalcogenide ma...Inexpensive,safe,and efficient conversion of solar energy to hydrogen from water splitting requires the development of effective and durable photocatalysts.Cu_(2)ZnSnS_(4)(CZTS),the emerging quaternary chalcogenide material for solar energy conversion,possesses many advantages,such as narrow direct band gap(1.5 eV),nontoxic,earth-abundance,and low melting point.Currently,CZTS-based photocatalysts have been extensively investigated for their application as an active photocatalyst in hydrogen evolution from water splitting,while the performance is still highly needed to be improved for the practical applications.In this review,first,the crystal and band structure properties of CZTS are briefly introduced,and afterward,the basic principle of photocatalytic hydrogen evolution from water splitting is discussed.Subsequently,the performance and status of bare CZTS,the combination of CZTS and co-catalysts,and CZTSbased heterojunction photocatalysts for hydrogen evolution are reviewed and discussed in detail.Finally,the issues and challenges currently encountered in the application of CZTS and their possible solutions for developing advanced CZTS photocatalysts are provided.展开更多
Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)thin film solar cells have been regarded as one of the most promising thin film photovoltaic technologies,offering a low-cost and environmentally friendly solar energy option.Alth...Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)thin film solar cells have been regarded as one of the most promising thin film photovoltaic technologies,offering a low-cost and environmentally friendly solar energy option.Although remarkable advances have been achieved in kesterite solar cells,the performance gap relative to mature thin film photovoltaic technologies such as CIGSe and Cd Te remains large.Significant open-circuit voltage(V_(OC))deficit has been recognized as the main limiting factor to performance improvement,with undesirable intrinsic defects being a key culprit contributing to the low V_(OC).To realize the promise inherent in kesterite CZTS to become an earth-abundant alternative to existing thin film photovoltaic technologies with comparable performance,significant research effort has been invested to tackle the challenging defect issues.In this review,recent progress and achievements relevant to engineering improvements to the defect properties of the semiconductor have been examined and summarized.Promising strategies include:(i)manipulating the synthesis process to obtain a desirable reaction pathway and chemical environment;(ii)introducing cation substitution to increase the ionic size difference and supress the related band tailing deep-level defects;(iii)applying post deposition treatment(PDT)with alkaline elements to passivate the detrimental defects.These advances obtained from work on kesterite solar cells may lead to future high performance from this material and may be further extended to other earth-abundant chalcogenide photovoltaic technologies.展开更多
文摘In this work,a Cu_(2)ZnSnS_(4)(CZTS)ingot is grown via a melting method,then cooled;the resulting molten stoichiomet-ric mixture is sealed off in a quartz ampoule under vacuum.The CZTS powder chemical composition analyses are determined us-ing energy dispersive spectroscopy,and revealing the slightly Cu-rich and Zn-poor character of the ingot.Powder X-ray diffrac-tion analysis reveals a crystalline structure with a kesterite phase formation,and a preferred orientation of(112)plane.The lat-tice constants of the a-and c-axes,calculated based on the XRD analyses,are a=5.40Åand c=10.84Å.Based on Hall measure-ments at room temperature,we find that the crystal exhibits p-type conductivity,with a high concentration of 1018 cm^(-3),a res-istivity of 1.7Ωcm,and a mobility of 10.69 cm^(2)V-1s-1.Activation energies are estimated based on an Arrhenius plot of conductiv-ity versus 1/T,for a temperature range of 80-350 K,measuring 35 and 160 meV in low-and high-temperature regimes,respect-ively,which is attributed to complex defects(2CuZn+SnZn)and antisite defects(CuZn),respectively.The observed scattering mech-anisms are attributed to ionized impurities and acoustic phonons at low and high temperatures,respectively.The extracted band-gap is 1.37 eV.
基金Supported by the National Natural Science Foundation of China (Grant No. 10574106)the Planned Science and Technology Project of Guangdong Province (Grant No.2003C05005)the Natural Science Fund of Zhanjiang Normal Univer-sity (Grant No.200801)
文摘Cu2ZnSnS4 (CZTS) thin films were successfully fabricated on glass substrates by sulfurizing Cu-Sn-Zn multilayer precursors, which were deposited by ion beam sputtering and RF magnetron sputtering, respectively. The structural, electrical and optical properties of the prepared films under various processing conditions were investigated in detail. Results showed that the as-deposited CZTS thin films with the precursors by both ion beam sputtering and RF magnetron sputtering have a composition near stoichiometric. The crystallization of the samples, however, has a strong dependence on the atomic percent of constituents of the prepared CZTS films. A single phase stannite-type structure CZTS with a large absorption coefficient of 104/cm in the visible range could be obtained after sulfurization at 520℃ for 2 h. The samples relative to the RF magnetron sputtering showed a low resistivity of 0.073 ?cm and band gap energy of about 1.53 eV. The samples relative to the ion beam sputtering exhibited a resistivity of 0.36 Ωcm and the band gap energy is about 1.51 eV.
基金financially supported by the Natural Science Foundation of Hainan Province (No. 521RC495)Key Research and Development Project of Hainan Province (Nos. ZDYF2020037 and ZDYF2020207)+2 种基金the National Natural Science Foundation of China (Nos. 6210031211 and 21805104)Innovative Research Projects for Graduate Students of Hainan Province (No. Hyb2020-05)the Start-Up Research Foundation of Hainan University (Nos. KYQD(ZR)-20008, 20082, 20083, 20084, 21065)
文摘Inexpensive,safe,and efficient conversion of solar energy to hydrogen from water splitting requires the development of effective and durable photocatalysts.Cu_(2)ZnSnS_(4)(CZTS),the emerging quaternary chalcogenide material for solar energy conversion,possesses many advantages,such as narrow direct band gap(1.5 eV),nontoxic,earth-abundance,and low melting point.Currently,CZTS-based photocatalysts have been extensively investigated for their application as an active photocatalyst in hydrogen evolution from water splitting,while the performance is still highly needed to be improved for the practical applications.In this review,first,the crystal and band structure properties of CZTS are briefly introduced,and afterward,the basic principle of photocatalytic hydrogen evolution from water splitting is discussed.Subsequently,the performance and status of bare CZTS,the combination of CZTS and co-catalysts,and CZTSbased heterojunction photocatalysts for hydrogen evolution are reviewed and discussed in detail.Finally,the issues and challenges currently encountered in the application of CZTS and their possible solutions for developing advanced CZTS photocatalysts are provided.
基金supported by the Australian Renewable Energy Agency(Grant Nos.1-USO028,and 2017/RND006)the Australian Research Council(ARC)Future Fellowship Programme(Grant No.FT190100756)the ACAP Postdoctoral Fellowship Supported by Australian Centre for Advanced Photovoltaics(Grant No.1-SRI001)。
文摘Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)thin film solar cells have been regarded as one of the most promising thin film photovoltaic technologies,offering a low-cost and environmentally friendly solar energy option.Although remarkable advances have been achieved in kesterite solar cells,the performance gap relative to mature thin film photovoltaic technologies such as CIGSe and Cd Te remains large.Significant open-circuit voltage(V_(OC))deficit has been recognized as the main limiting factor to performance improvement,with undesirable intrinsic defects being a key culprit contributing to the low V_(OC).To realize the promise inherent in kesterite CZTS to become an earth-abundant alternative to existing thin film photovoltaic technologies with comparable performance,significant research effort has been invested to tackle the challenging defect issues.In this review,recent progress and achievements relevant to engineering improvements to the defect properties of the semiconductor have been examined and summarized.Promising strategies include:(i)manipulating the synthesis process to obtain a desirable reaction pathway and chemical environment;(ii)introducing cation substitution to increase the ionic size difference and supress the related band tailing deep-level defects;(iii)applying post deposition treatment(PDT)with alkaline elements to passivate the detrimental defects.These advances obtained from work on kesterite solar cells may lead to future high performance from this material and may be further extended to other earth-abundant chalcogenide photovoltaic technologies.
