The carbon-based CsPbI_XBr_(3-X)all-inorganic perovskite is emerging as one of the most promising photovoltaic materials for single-junction or tandem solar cells,owing to its low fabrication cost and tunable bandgap....The carbon-based CsPbI_XBr_(3-X)all-inorganic perovskite is emerging as one of the most promising photovoltaic materials for single-junction or tandem solar cells,owing to its low fabrication cost and tunable bandgap.Currently,organic passivants in common use usually bind to a single active site and tend to result in dense packing of passivants aligned perpendicular to the surface,which may introduce a transport barrier at the perovskite/carbon electrode interface.In this study,chlorothalonil(TPN),a"bactericide"with multiple reactive sites,was employed to"sterilize"the surface of CsPbI_(2.75)Br_(0.25)perovskite.TPN,featuring two symmetrically arranged cyano groups and four chlorine atoms,can simultaneously anchor two uncoordinated Pb^(2+)ions through Lewis acid-base interactions while passivating halogen vacancy defects,thereby effectively suppressing non-radiative recombination.Theoretical calculations and experimental results reveal that multiple reactive sites enable TPN to adopt a planar arrangement on perovskite surfaces,forming ultrathin passivation layer that mitigates charge transport barriers.Concurrently,this planar configuration exposes benzene rings outward,which establishes gradient energy-level alignment,thereby enhancing hole extraction efficiency and improving perovskite hydrophobicity.As a result,the PCE of the HTL-free CsPbI_(2.75)Br_(0.25)C-PSCs increased from 16.94%for the control device to 18.23%after TPN"sterilization",with an impressive FF of 81.06%.展开更多
基金financially supported by the National Natural Science Foundation of China(No.62305015,No.22005013)Beijing Institute of Graphic Communication Project(No.Ea202503)Analytical&Testing Center,Beihang University,for its support in this work。
文摘The carbon-based CsPbI_XBr_(3-X)all-inorganic perovskite is emerging as one of the most promising photovoltaic materials for single-junction or tandem solar cells,owing to its low fabrication cost and tunable bandgap.Currently,organic passivants in common use usually bind to a single active site and tend to result in dense packing of passivants aligned perpendicular to the surface,which may introduce a transport barrier at the perovskite/carbon electrode interface.In this study,chlorothalonil(TPN),a"bactericide"with multiple reactive sites,was employed to"sterilize"the surface of CsPbI_(2.75)Br_(0.25)perovskite.TPN,featuring two symmetrically arranged cyano groups and four chlorine atoms,can simultaneously anchor two uncoordinated Pb^(2+)ions through Lewis acid-base interactions while passivating halogen vacancy defects,thereby effectively suppressing non-radiative recombination.Theoretical calculations and experimental results reveal that multiple reactive sites enable TPN to adopt a planar arrangement on perovskite surfaces,forming ultrathin passivation layer that mitigates charge transport barriers.Concurrently,this planar configuration exposes benzene rings outward,which establishes gradient energy-level alignment,thereby enhancing hole extraction efficiency and improving perovskite hydrophobicity.As a result,the PCE of the HTL-free CsPbI_(2.75)Br_(0.25)C-PSCs increased from 16.94%for the control device to 18.23%after TPN"sterilization",with an impressive FF of 81.06%.
