Unraveling abnormal buried interface anion defect passivation mechanisms depending on cation-induced steric hindrance for efficient and stable perovskite solar cells  

作　　者：Dongmei He Ru Li Baibai Liu Qian Zhou Hua Yang Xuemeng Yu Shaokuan Gong Xihan Chen Baomin Xu Shangfeng Yang Jiangzhao Chen 

机构地区：[1]Key Laboratory of Optoelectronic Technology&Systems(Ministry of Education),College of Optoelectronic Engineering,Chongqing University,Chongqing 400044,China [2]Institute of High Energy Physics,Chinese Academy of Sciences(CAS),Bejing 100049,Chin [3]SUSTech Energy Institute for Carbon Neutrality,Department of Mechanical and Energy Engineering,Southern University of Science and Technology,Shenzhen 518055,Guangdong,Chin [4]Department of Materials Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,Guangdong,China [5]CAS Key Laboratory of Materials for Energy Conversion,Department of Materials Science and Engineering,University of Science and Technology of China,Hefei 230026,Anhui,China

出　　处：《Journal of Energy Chemistry》2023年第5期1-9,I0001,共10页能源化学（英文版）

基　　金：financially supported by the Support Plan for Overseas Students to Return to China for Entrepreneurship and Innovation(cx2020003);the Fundamental Research Funds for the Central Universities(2020CDJ-LHZZ-074 and 2021CDJQY-022);Natural Science Foundation of Chongqing(cstc2020jcyjmsxmX0629)。

摘　　要：Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal an abnormal buried interface anion defect passivation mechanism depending on cationinduced steric hindrance.The IL molecules containing the same anion([BF4]^(-))and different sizes of imidazolium cations induced by substituent size are used to manipulate buried interface.It was revealed what passivated interfacial defects is mainly anions instead of cations.Theoretical and experimental results demonstrate that the large-sized cations can weaken the ionic bond strength between anions and cations,and facilitate the interaction between anions and SnO2as well as perovskites,which is conducive to interfacial defect passivation and ameliorating interfacial contact.It can be concluded that interfacial chemical interaction strength and defect passivation effect are positively correlated with the size of cations.The discovery breaks conventional thinking that large-sized modification molecules would weaken their chemical interaction with perovskite.Compared with the control device(21.54%),the device based on 1,3-Bis(1-adamantyl)-imidazolium tetrafluoroborate(BAIMBF4)with maximum size cations achieves a significantly enhanced efficiency of 23.61%along with much increased moisture,thermal and light stabilities.

关 键 词：Perovskite solar cells Buried interface Ionic liquid Anion defect passivation mechanism Cation-induced steric hindrance 

分 类 号：TM914.4[电气工程—电力电子与电力传动]