The Knudsen effusion cell is often used to grow high-quality Cu(In,Ga)Se_(2)(CIGS)thin film in coevaporation processes.However,the traditional single-heating Knudsen effusion cell cannot deliver complete metal selenid...The Knudsen effusion cell is often used to grow high-quality Cu(In,Ga)Se_(2)(CIGS)thin film in coevaporation processes.However,the traditional single-heating Knudsen effusion cell cannot deliver complete metal selenides during the whole deposition process,particularly for a low-temperature deposition process,which is probably due to the condensation and droplet ejection at the nozzle of the crucible.In this study,thermodynamics analysis is conducted to decipher the reason for this phenomenon.Furthermore,a new single-heating Knudsen effusion is proposed to solve this difficult problem,which leads to an improvement in the quality of CIGS film and a relative increase in conversion efficiency of 29%at a growth rate of about 230 nmmin1,compared with the traditional efficiency in a lowtemperature rapid-deposition process.展开更多
Cu(In,Ga)Se_(2)(CIGS)is a promising candidate to replace crystalline silicon solar cells and dominate the photovoltaic market in the future.Alkali elements such as sodium(Na),potassium(K),rubidium(Rb),and Cesium(Cs)ar...Cu(In,Ga)Se_(2)(CIGS)is a promising candidate to replace crystalline silicon solar cells and dominate the photovoltaic market in the future.Alkali elements such as sodium(Na),potassium(K),rubidium(Rb),and Cesium(Cs)are commonly accepted as indispensable parts to boost cell efficiencies of CIGS thin-film solar cells.Therefore,a comprehensive understanding of alkali effects on the electronic and chemical properties of the CIGS layer as well as the underlying mechanisms is of paramount importance for achieving high-performance solar cells.This paper reviews the development process and incorporation pathways of alkalis and then overviews the roles of different alkali elements and their effects on CIGS cells in detail.Furthermore,the unsolved problems and future development prospects are also proposed.Overall,the understanding and development of widely adopted alkali-fluoride post-deposition treatments(PDTs)are still underway,and together with newly updated research,it will likely enable the CIGS technology to make the conversion efficiency closer to its theoretical limit.展开更多
Chalcopyrite Cu(In,Ga)Se_(2)(CIGS) thin films deposited in a low-temperature process(450℃) usually produce fine grains and poor crystallinity. Herein, different Ag treatment processes, which can decrease the melting ...Chalcopyrite Cu(In,Ga)Se_(2)(CIGS) thin films deposited in a low-temperature process(450℃) usually produce fine grains and poor crystallinity. Herein, different Ag treatment processes, which can decrease the melting temperature and enlarge band gap of the CIGS films, were employed to enhance the quality of thin films in a low-temperature deposition process. It is demonstrated that both the Ag precursor and Ag surface treatment process can heighten the crystallinity of CIGS films and the device efficiency. The former is more obvious than the latter. Furthermore, the Urbach energy is also reduced with Ag doping. This work aims to provide a feasible Ag-doping process for the high-quality CIGS films in a low-temperature process.展开更多
基金The work was supported by the National Key R&D Program of China(2018YFB1500200)the National Natural Science Foundation of China(61774089 and 61974076)the Natural Science Foundation of Tianjin(18JCZDJC31200).
文摘The Knudsen effusion cell is often used to grow high-quality Cu(In,Ga)Se_(2)(CIGS)thin film in coevaporation processes.However,the traditional single-heating Knudsen effusion cell cannot deliver complete metal selenides during the whole deposition process,particularly for a low-temperature deposition process,which is probably due to the condensation and droplet ejection at the nozzle of the crucible.In this study,thermodynamics analysis is conducted to decipher the reason for this phenomenon.Furthermore,a new single-heating Knudsen effusion is proposed to solve this difficult problem,which leads to an improvement in the quality of CIGS film and a relative increase in conversion efficiency of 29%at a growth rate of about 230 nmmin1,compared with the traditional efficiency in a lowtemperature rapid-deposition process.
基金supported by the National Natural Science Foundation of China(Nos.11975135 and 61176003)financial support of Special Funds for Fundamental Research Funds for Central Universities(No.2018 NTST29)the Chinese Postdoctoral Science Foundation(No.2019M650524)。
文摘Cu(In,Ga)Se_(2)(CIGS)is a promising candidate to replace crystalline silicon solar cells and dominate the photovoltaic market in the future.Alkali elements such as sodium(Na),potassium(K),rubidium(Rb),and Cesium(Cs)are commonly accepted as indispensable parts to boost cell efficiencies of CIGS thin-film solar cells.Therefore,a comprehensive understanding of alkali effects on the electronic and chemical properties of the CIGS layer as well as the underlying mechanisms is of paramount importance for achieving high-performance solar cells.This paper reviews the development process and incorporation pathways of alkalis and then overviews the roles of different alkali elements and their effects on CIGS cells in detail.Furthermore,the unsolved problems and future development prospects are also proposed.Overall,the understanding and development of widely adopted alkali-fluoride post-deposition treatments(PDTs)are still underway,and together with newly updated research,it will likely enable the CIGS technology to make the conversion efficiency closer to its theoretical limit.
基金The work was supported by the National Key R&D Program of China(No.2018YFB1500200)National Natural Science Foundation of China(Nos.61774089 and 61974076)Natural Science Foundation of Tianjin(No.18JCZDJC31200)。
文摘Chalcopyrite Cu(In,Ga)Se_(2)(CIGS) thin films deposited in a low-temperature process(450℃) usually produce fine grains and poor crystallinity. Herein, different Ag treatment processes, which can decrease the melting temperature and enlarge band gap of the CIGS films, were employed to enhance the quality of thin films in a low-temperature deposition process. It is demonstrated that both the Ag precursor and Ag surface treatment process can heighten the crystallinity of CIGS films and the device efficiency. The former is more obvious than the latter. Furthermore, the Urbach energy is also reduced with Ag doping. This work aims to provide a feasible Ag-doping process for the high-quality CIGS films in a low-temperature process.
