Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free p...Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free perovskite solar cells.However,due to the unique and inherent characteristics of Sn^(2+)being easily oxidized to Sn^(4+)and fast crystallization,tin perovskite solar cells(TPSCs)show relatively poor performance and stability,compared to the lead counterparts.Recently,the introduction of bulky organic spacers into three-dimensional(3D)THPs for dimensional regulation can not only prevent the intrusion of water and oxygen,but also inhibit the self-doping effect and ion migration.In this review,we will detail how dimensional regulation enables TPSCs with high performance and superior stability.First,we summarize the intrinsic properties of THPs and analyze the root causes of their poor performance and instability.Next,we discuss the specific structure and types of the dimensional regulation strategy.Then,the mechanism of dimensional regulation is discussed in detail,mainly from inhibiting the Sn^(2+)oxidation,optimizing crystallization,passivating defects,and improving energy level alignment.Finally,future challenges and prospects for dimensional regulation are elaborated to help researchers develop more efficient and stable TPSCs.展开更多
Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on a...Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on ammonium,whereas formamidinium(FA^(+))has been seldom applied despite that FA has been extensively used in high-efficiency 3D PSCs.Herein,a novel FA-based organic spacer cation,4-chloro-phenylformamidinium(CPFA^(+)),is applied in quasi-2D Ruddlesden-Popper(RP)PSCs for the first time,and methylammonium chloride(MACl)is employed to promote crystal growth and orientation of perovskite film,resulting in high power conversion efficiency(PCE)with improved stability.Upon incorporating CPFA+organic spacer cation and MACl additive,high-quality quasi-2D CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)perovskite film forms,exhibiting improved crystal orientation,reduced trap state density,prolonged carrier lifetime and optimized energy level alignment.Consequently,the CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)quasi-2D RP PSC devices deliver a highest PCE of 14.78%.Moreover,the un-encapsulated CPFA-based quasi-2D RP PSC devices maintain~80%of its original PCE after exceeding 2000 h storage under ambient condition,whereas the 3D MAPb I3counterparts retain only~45%of its original PCE.Thus,the ambient stability of quasi-2D RP PSC devices is improved obviously relative to its 3D MAPb I3counterpart.展开更多
基金financially supported by the National Natural Science Foundation of China(51702038)the Science&Technology Department of Sichuan Province(2020YFG0061)+2 种基金the Recruitment Program for Young Professionalsthe National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial support。
文摘Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free perovskite solar cells.However,due to the unique and inherent characteristics of Sn^(2+)being easily oxidized to Sn^(4+)and fast crystallization,tin perovskite solar cells(TPSCs)show relatively poor performance and stability,compared to the lead counterparts.Recently,the introduction of bulky organic spacers into three-dimensional(3D)THPs for dimensional regulation can not only prevent the intrusion of water and oxygen,but also inhibit the self-doping effect and ion migration.In this review,we will detail how dimensional regulation enables TPSCs with high performance and superior stability.First,we summarize the intrinsic properties of THPs and analyze the root causes of their poor performance and instability.Next,we discuss the specific structure and types of the dimensional regulation strategy.Then,the mechanism of dimensional regulation is discussed in detail,mainly from inhibiting the Sn^(2+)oxidation,optimizing crystallization,passivating defects,and improving energy level alignment.Finally,future challenges and prospects for dimensional regulation are elaborated to help researchers develop more efficient and stable TPSCs.
基金supported by the National Key Research and Development Program of China(2017YFA0402800)the National Natural Science Foundation of China(51925206,U1932214)。
文摘Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on ammonium,whereas formamidinium(FA^(+))has been seldom applied despite that FA has been extensively used in high-efficiency 3D PSCs.Herein,a novel FA-based organic spacer cation,4-chloro-phenylformamidinium(CPFA^(+)),is applied in quasi-2D Ruddlesden-Popper(RP)PSCs for the first time,and methylammonium chloride(MACl)is employed to promote crystal growth and orientation of perovskite film,resulting in high power conversion efficiency(PCE)with improved stability.Upon incorporating CPFA+organic spacer cation and MACl additive,high-quality quasi-2D CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)perovskite film forms,exhibiting improved crystal orientation,reduced trap state density,prolonged carrier lifetime and optimized energy level alignment.Consequently,the CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)quasi-2D RP PSC devices deliver a highest PCE of 14.78%.Moreover,the un-encapsulated CPFA-based quasi-2D RP PSC devices maintain~80%of its original PCE after exceeding 2000 h storage under ambient condition,whereas the 3D MAPb I3counterparts retain only~45%of its original PCE.Thus,the ambient stability of quasi-2D RP PSC devices is improved obviously relative to its 3D MAPb I3counterpart.