标题：A Gradient Heterostructure Based on Tolerance Factor in High-Performance Perovskite Solar Cells with 0.84 Fill Factor
作者：Qiao, Hong Wei; Yang, Shuang; Wang, Yun; Chen, Xiao; Wen, Tian Yu; Tang, Li Juan; Cheng, Qilin; Hou, Yu; Zhao, Huijun; Yang, Hua Gui
作者机构：[Qiao, Hong Wei; Chen, Xiao; Wen, Tian Yu; Tang, Li Juan; Cheng, Qilin; Hou, Yu; Yang, Hua Gui] East China Univ Sci & Technol, Key Lab Ultrafine Mat, 更多
通讯作者：Hou, Y;Yang, HG;Zhao, HJ;Hou, Yu
通讯作者地址：[Hou, Y; Yang, HG]East China Univ Sci & Technol, Key Lab Ultrafine Mat, Minist Educ, Sch Mat Sci & Engn, Shanghai 200237, Peoples R China;[Zhao, HJ]Gr 更多
关键词：charge transfer; fill factor; gradient heterostructures; perovskite; solar cells; tolerance factor
摘要：A gradient heterosturcture is one of the basic methods to control the charge flow in perovskite solar cells (PSCs). However, a classical route for gradient heterosturctures is based on the diffusion technique, in which the guest ions gradually diffuse into the films from a concentrated source of dopants. The gradient heterosturcture is only accessible to the top side, and may be time consuming and costly. Here, the "intolerant" n-type heteroatoms (Sb3+, In3+) with mismatched cation sizes and charge states can spontaneously enrich two sides of perovskite thin films. The dopants at specific sides can be extracted by a typical hole-transport layer. Theoretical calculations and experimental observations both indicate that the optimized charge management can be attributed to the tailored band structure and interfacial electronic hybridization, which promote charge separation and collection. The strategy enables the fabrication of PSCs with a spontaneous graded heterojunction showing high efficiency. A champion device based on Sb3+ doped film shows a stabilized power-conversion efficiency of 21.04% with a high fill factor of 0.84 and small hysteresis.