Aqueous precursors provide an alluring approach for low-cost and environmentally friendly production of earth-abundant Cu2ZnSn(S,Se)4(CZTSSe)solar cells.The key is to find an appropriate molecular agent to prepare a s...Aqueous precursors provide an alluring approach for low-cost and environmentally friendly production of earth-abundant Cu2ZnSn(S,Se)4(CZTSSe)solar cells.The key is to find an appropriate molecular agent to prepare a stable solution and optimize the coordination structure to facilitate the subsequent crystallization process.Herein,we introduce thioglycolic acid(TGA),which possesses strong coordination(SH)and hydrophilic(COOH)groups,as the agent and use deprotonation to regulate the coordination competition within the aqueous solution.Ultimately,metal cations are adequately coordinated with thiolate anions,and carboxylate anions are released to become hydrated to form an ultrastable aqueous solution.These factors have contributed to achieving CZTSSe solar cells with an efficiency as high as 12.3%(a certified efficiency of 12.0%)and providing an extremely wide time window for precursor storage and usage.This work represents significant progress in the non-toxic solution fabrication of CZTSSe solar cells and holds great potential for the development of CZTSSe and other metal sulfide solar cells.展开更多
In-situ prepared MoO3 thin layer has been introduced to suppress the formation of too thick Mo(S,Se)2layer in Cu2ZnSnSxSe4–x(CZTSSe) solar cells. This MoO3 layer effectively improves the back interfacial contact betw...In-situ prepared MoO3 thin layer has been introduced to suppress the formation of too thick Mo(S,Se)2layer in Cu2ZnSnSxSe4–x(CZTSSe) solar cells. This MoO3 layer effectively improves the back interfacial contact between CZTSSe absorber layer and Mo substrate without poisoning the carrier transport. Up to 10.58% power conversion efficiency has been achieved.展开更多
Although Cu2ZnSn(Sx,Se1-x)4(CZTSSe)is a promising candidate for thin-film photovoltaics,its cell performance is currently limited by the large voltage loss.Although a series of studies on the efficiency loss mechanism...Although Cu2ZnSn(Sx,Se1-x)4(CZTSSe)is a promising candidate for thin-film photovoltaics,its cell performance is currently limited by the large voltage loss.Although a series of studies on the efficiency loss mechanism of CZTSSe solar cell have been carried out in the past few years,no convincing understanding has been obtained until now.In this review,the current findings regarding the underlying mechanism of the efficiency loss in CZTSSe solar cells are systematically summarized and analyzed.The properties of atomic disorder and deep defects in CZTSSe materials and their effects on device performance are discussed.The synergistic effect is proposed to help understand the defect-related charge loss in the absorber.Furthermore,the experimental methods of defect identification and defect control are presented,in an attempt to identify the killer defects that can be responsible for the ultra-short minority lifetime of CZTSSe material.By comprehensively and dialectically understanding these defect properties of the CZTSSe solar cell,we believe breakthrough in the cell efficiency will come soon with our concentrated effort.展开更多
Intrinsic and extrinsic ion migration is a very large threat to the operational stability of perovskite solar cells and is difficult to completely eliminate due to the low activation energy of ion migration and the ex...Intrinsic and extrinsic ion migration is a very large threat to the operational stability of perovskite solar cells and is difficult to completely eliminate due to the low activation energy of ion migration and the existence of internal electric field.We propose a heterojunction route to help suppress ion migration,thus improving the operational stability of the cell from the perspective of eliminating the electric field response in the perovskite absorber.A heavily doped p-type(p^(+))thin layer semiconductor is introduced between the electron transporting layer(ETL)and perovskite absorber.The heterojunction charge depletion and electric field are limited to the ETL and p^(+)layers,while the perovskite absorber and hole transporting layer remain neutral.The p^(+)layer has a variety of candidate materials and is tolerant of defect density and carrier mobility,which makes this heterojunction route highly feasible and promising for use in practical applications.展开更多
A study of the self-healing phenomenon of Cu2ZnSn（S, Se）4（CZTSSe） solar cells has shown more than 10% enhancement in cell performance after storage at room temperature for a week, with a significant improvement in...A study of the self-healing phenomenon of Cu2ZnSn（S, Se）4（CZTSSe） solar cells has shown more than 10% enhancement in cell performance after storage at room temperature for a week, with a significant improvement in the open-circuit photovoltage（V（oc）） and fill factor（F F）. In addition, up to 10.45% power conversion efficiency（PCE） has been achieved.No obvious change in crystallinity, crystal phase, optical absorption or elemental distribution in the CZTSSe films was detected on examining the x-ray diffraction（XRD） pattern, Raman spectrum, ultraviolet-visible（UV-Vis）, and TOF-SIMS.Further investigations on the charge carrier concentration, charge radiative recombination, and band structure suggest that the enhancement in PCE stems mainly from a reduction in deep defects of the CZTSSe semiconductor film.展开更多
Due to distinctive lattice and electronic properties,the thiocyanate anion(SCN-)perovskite as an alluring two-dimensional(2D)material system,can be applied in optoelectronic devices.Herein,both photovoltaic and photod...Due to distinctive lattice and electronic properties,the thiocyanate anion(SCN-)perovskite as an alluring two-dimensional(2D)material system,can be applied in optoelectronic devices.Herein,both photovoltaic and photodetection performances of the 2D Cs2Pb(SCN)2I2 have been investigated.Compared with the conventional cationic 2D perovskites,Cs2Pb(SCN)2I2 possesses ultra-small interlayer spacing,additional interlayer nano channels,which is thus beneficial for charge transport ability.The planar heterojunction solar cell based on Cs2Pb(SCN)2I2 as the light absorber,has presented the highest power conversion efficiency among long-chain-cation-based 2D perovskite devices.Besides,the Cs2Pb(SCN)2I2-based photodetector also exhibits much higher photodetection performance(i.e.quantum efficiency,on/off ratio,responsivity,detectivity,response speed,polarization sensitivity and detection stability).It is thus suggested that these outstanding photoelectric characteristics of Cs2Pb(SCN)2I2 could bring huge opportunities for its more abundant optoelectronic applications,such as field-effect transistor and light-emitting diodes.展开更多
The Zn/Sn ratio in Cu2ZnSn（S, Se）4 （CZTSSe） films has been regulated to control the composition-related phase, defect, and photoelectric properties for high performance kesterite solar cells. It is found that the ...The Zn/Sn ratio in Cu2ZnSn（S, Se）4 （CZTSSe） films has been regulated to control the composition-related phase, defect, and photoelectric properties for high performance kesterite solar cells. It is found that the increase in the Zn/Sn ratio can slightly narrow the energy band gap to extend the light absorption range and improve the photocurrent. Optimal Zn/Sn ratio of 1.39 in CZTSSe film is obtained with the least secondary phase, the lowest defect density, and the longest charge recombination lifetime. Up to 10.1% photoelectric conversion efficiency has been achieved by this composition regulation.展开更多
基金supported by the National Natural Science Foundation of China(51961165108,51421002,51972332 and 51627803)。
文摘Aqueous precursors provide an alluring approach for low-cost and environmentally friendly production of earth-abundant Cu2ZnSn(S,Se)4(CZTSSe)solar cells.The key is to find an appropriate molecular agent to prepare a stable solution and optimize the coordination structure to facilitate the subsequent crystallization process.Herein,we introduce thioglycolic acid(TGA),which possesses strong coordination(SH)and hydrophilic(COOH)groups,as the agent and use deprotonation to regulate the coordination competition within the aqueous solution.Ultimately,metal cations are adequately coordinated with thiolate anions,and carboxylate anions are released to become hydrated to form an ultrastable aqueous solution.These factors have contributed to achieving CZTSSe solar cells with an efficiency as high as 12.3%(a certified efficiency of 12.0%)and providing an extremely wide time window for precursor storage and usage.This work represents significant progress in the non-toxic solution fabrication of CZTSSe solar cells and holds great potential for the development of CZTSSe and other metal sulfide solar cells.
基金financially supported by the National Natural Science Foundation of China (91733301, 51761145042, 51627803, 21501183, 51402348, 11474333, 91433205 and 51421002)the Knowledge Innovation Program and the Strategic Priority Research Program (Grant XDB 12010400) of the Chinese Academy of Sciences
文摘In-situ prepared MoO3 thin layer has been introduced to suppress the formation of too thick Mo(S,Se)2layer in Cu2ZnSnSxSe4–x(CZTSSe) solar cells. This MoO3 layer effectively improves the back interfacial contact between CZTSSe absorber layer and Mo substrate without poisoning the carrier transport. Up to 10.58% power conversion efficiency has been achieved.
基金supported by the National Natural Science Foundation of China(51961165108,51421002,51972332 and 51627803)。
文摘Although Cu2ZnSn(Sx,Se1-x)4(CZTSSe)is a promising candidate for thin-film photovoltaics,its cell performance is currently limited by the large voltage loss.Although a series of studies on the efficiency loss mechanism of CZTSSe solar cell have been carried out in the past few years,no convincing understanding has been obtained until now.In this review,the current findings regarding the underlying mechanism of the efficiency loss in CZTSSe solar cells are systematically summarized and analyzed.The properties of atomic disorder and deep defects in CZTSSe materials and their effects on device performance are discussed.The synergistic effect is proposed to help understand the defect-related charge loss in the absorber.Furthermore,the experimental methods of defect identification and defect control are presented,in an attempt to identify the killer defects that can be responsible for the ultra-short minority lifetime of CZTSSe material.By comprehensively and dialectically understanding these defect properties of the CZTSSe solar cell,we believe breakthrough in the cell efficiency will come soon with our concentrated effort.
基金supported by the National Natural Science Foundation of China(52072402,11874402,51627803,51421002,91733301,51761145042,and 51872321)the International Partnership Program of Chinese Academy of Sciences(112111KYSB20170089)。
文摘Intrinsic and extrinsic ion migration is a very large threat to the operational stability of perovskite solar cells and is difficult to completely eliminate due to the low activation energy of ion migration and the existence of internal electric field.We propose a heterojunction route to help suppress ion migration,thus improving the operational stability of the cell from the perspective of eliminating the electric field response in the perovskite absorber.A heavily doped p-type(p^(+))thin layer semiconductor is introduced between the electron transporting layer(ETL)and perovskite absorber.The heterojunction charge depletion and electric field are limited to the ETL and p^(+)layers,while the perovskite absorber and hole transporting layer remain neutral.The p^(+)layer has a variety of candidate materials and is tolerant of defect density and carrier mobility,which makes this heterojunction route highly feasible and promising for use in practical applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.91733301,51761145042,91433205,11474333,51421002,51627803,and51572288) the International Partnership Program of the Chinese Academy of Sciences(Grant No.112111KYSB20170089)
文摘A study of the self-healing phenomenon of Cu2ZnSn（S, Se）4（CZTSSe） solar cells has shown more than 10% enhancement in cell performance after storage at room temperature for a week, with a significant improvement in the open-circuit photovoltage（V（oc）） and fill factor（F F）. In addition, up to 10.45% power conversion efficiency（PCE） has been achieved.No obvious change in crystallinity, crystal phase, optical absorption or elemental distribution in the CZTSSe films was detected on examining the x-ray diffraction（XRD） pattern, Raman spectrum, ultraviolet-visible（UV-Vis）, and TOF-SIMS.Further investigations on the charge carrier concentration, charge radiative recombination, and band structure suggest that the enhancement in PCE stems mainly from a reduction in deep defects of the CZTSSe semiconductor film.
基金supported by the National Key R&D Program of China(2018YFB1500101)the National Natural Science Foundation of China(11874402,51421002,51627803,91733301 and 51761145042)the International Partnership Program of Chinese Academy of Sciences(112111KYSB20170089)。
文摘Due to distinctive lattice and electronic properties,the thiocyanate anion(SCN-)perovskite as an alluring two-dimensional(2D)material system,can be applied in optoelectronic devices.Herein,both photovoltaic and photodetection performances of the 2D Cs2Pb(SCN)2I2 have been investigated.Compared with the conventional cationic 2D perovskites,Cs2Pb(SCN)2I2 possesses ultra-small interlayer spacing,additional interlayer nano channels,which is thus beneficial for charge transport ability.The planar heterojunction solar cell based on Cs2Pb(SCN)2I2 as the light absorber,has presented the highest power conversion efficiency among long-chain-cation-based 2D perovskite devices.Besides,the Cs2Pb(SCN)2I2-based photodetector also exhibits much higher photodetection performance(i.e.quantum efficiency,on/off ratio,responsivity,detectivity,response speed,polarization sensitivity and detection stability).It is thus suggested that these outstanding photoelectric characteristics of Cs2Pb(SCN)2I2 could bring huge opportunities for its more abundant optoelectronic applications,such as field-effect transistor and light-emitting diodes.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51627803,51402348,51421002,51372270,and 51372272)the Knowledge Innovation Program of the Chinese Academy of Sciences
文摘The Zn/Sn ratio in Cu2ZnSn（S, Se）4 （CZTSSe） films has been regulated to control the composition-related phase, defect, and photoelectric properties for high performance kesterite solar cells. It is found that the increase in the Zn/Sn ratio can slightly narrow the energy band gap to extend the light absorption range and improve the photocurrent. Optimal Zn/Sn ratio of 1.39 in CZTSSe film is obtained with the least secondary phase, the lowest defect density, and the longest charge recombination lifetime. Up to 10.1% photoelectric conversion efficiency has been achieved by this composition regulation.
