MA Cation-Induced Diffusional Growth of Low-Bandgap FA-Cs Perovskites Driven by Natural Gradient Annealing

作     者：Taiyang Zhang Yuetian Chen Miao Kan Shumao Xu Yanfeng Miao Xingtao Wang Meng Ren Haoran Chen Xiaomin Liu Yixin Zhao Taiyang Zhang;Yuetian Chen;Miao Kan;Shumao Xu;Yanfeng Miao;Xingtao Wang;Meng Ren;Haoran Chen;Xiaomin Liu;Yixin Zhao

作者机构：School of Environmental Science and EngineeringShanghai Jiao Tong University800 Dongchuan Rd.Shanghai 200240China Shanghai Institute of Pollution Control and Ecological SecurityShanghai 200240China 

出 版 物：《Research》 (研究（英文）)

年 卷 期：2021年第2021卷第1期

页      面：748-758页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：support of the NSFC(Grant Nos.22025505 and 21777096) Program of Shanghai Academic/-Technology Research Leader(Grant No.20XD1422200) Cultivating fund of Frontiers Science Center for Transformative Molecules(2019PT02) TZ acknowledges the support of the Initiative Postdocs Supporting Program(Grant No.BX20180185) China Postdoctoral Science Foundation(Grant No.2018M640387) 

主　　题：temperature annealing perovskite 

摘      要：Low-bandgap formamidinium-cesium(FA-Cs)perovskites of FA_(1-x)CsxPbI_(3)(x0:1)are promising candidates for efficient and robust perovskite solar cells,but their black-phase crystallization is very sensitive to annealing ***,the low heat conductivity of the glass substrate builds up a temperature gradient within from bottom to top and makes the initial annealing temperature of the perovskite film lower than the black-phase crystallization point(~150℃).Herein,we take advantage of such temperature gradient for the diffusional growth of high-quality FA-Cs perovskites by introducing a thermally unstable MA^(+)cation,which would firstly formα-phase FA-MA-Cs mixed perovskites with low formation energy at the hot bottom of the perovskite films in the early annealing *** natural gradient annealing temperature and the thermally unstable MA^(+)cation then lead to the bottom-to-top diffusional growth of highly orientatedα-phase FA-Cs perovskite,which exhibits 10-fold of enhanced crystallinity and reduced trap density(~3:85×10^(15) cm^(−3)).Eventually,such FA-Cs perovskite films were fabricated into stable solar cell devices with champion efficiency up to 23.11%,among the highest efficiency of MA-free perovskite solar cells.