Improved phase stability of CsPbI2Br perovskite by released microstrain toward highly efficient and stable solar cells  

作　　者：Kanghui Zheng Jinfeng Ge Chang Liu Qiang Lou Xia Chen Yuanyuan Meng Xu Yin Shixiao Bu Cuirong Liu Ziyi Ge 

机构地区：[1]Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo,China [2]College of Materials Technology and Engineering,Taiyuan University of Science and Technology,Taiyuan,China [3]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing,China

出　　处：《InfoMat》2021年第12期1431-1444,共14页信息材料（英文）

基　　金：CAS Key Project of Frontier Science Research,Grant/Award Number:QYZDBSSW-SYS030;National Natural Science Foundation of China,Grant/Award Numbers:22005322,51773212,81903743;National Science Fund for Distinguished Young Scholars,Grant/Award Number:21925506;Ningbo S&T Innovation 2025 Major Special Programme,Grant/Award Number:2018B10055;National Key R&D Program of China,Grant/Award Number:2017YFE0106000。

摘　　要：All-inorganic perovskite solar cells(PSCs)have developed rapidly in the field of photovoltaics due to their excellent thermal and light stability.However,compared with organic–inorganic hybrid perovskites,the phase instability of inorganic perovskite under humidity still remains as a critical issue that ham-pers the commercialization of inorganic PSCs.We originally propose in this work that microstrains between the perovskite lattices/grains play a key role in affecting the phase stability of inorganic perovskite.To this end,we inno-vatively design theπ-conjugated p-type molecule bis(2-ethylhexyl)3,30((4,8-bis(5-(2-ethylhexyl)-3,4-difluorothiophen-2-yl)benzo[1,2-b:4,5-b0]dithiophene-2,6-di yl)bis(3,300-dioctyl[2,20:50,200-terthiophene]-500,5-diyl))(2E,20 E)-bis(2-cyanoacrylate)(BTEC-2F)to covalent with the Pb dangling bonds in CsPbI2Br perovskite film,which significantly suppress the trap states and release the defect-induced local stress between perovskite grains.The interplay between the microstrains and phase stability of the inorganic perovskite are scrutinized by a series of charac-terizations including x-ray photoelectron spectroscopy,photoluminescence,x-ray diffraction,scanning electron microscopy,and so forth,based on which,we conclude that weaker local stresses in the perovskite film engender superior phase stability by preventing the perovskite lattice distortion under humidity.By this rational design,PSCs based on CsPbI2Br perovskite system deliver an outstanding power conversion efficiency(PCE)up to 16.25%.The unencapsulated device also exhibits an exceptional moisture stability by retaining over 80%of the initial PCE after 500 h aging in ambient with relative humidity of(RH)25%.

关 键 词：CsPbI2Br interface modification microstrains phase stability π-conjugated small molecule 

分 类 号：O61[理学—无机化学]