Gelation of Hole Transport Layer to Improve the Stability of Perovskite Solar Cells  

作　　者：Ying Zhang Chenxiao Zhou Lizhi Lin Fengtao Pei Mengqi Xiao Xiaoyan Yang Guizhou Yuan Cheng Zhu Yu Chen Qi Chen 

机构地区：[1]Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications,MIIT Key Laboratory for Low‑Dimensional Quantum Structure and Devices,Experimental Center of Advanced Materials,School of Materials Science and Engineering,Beijing Institute of Technology,Beijing 100081,People’s Republic of China

出　　处：《Nano-Micro Letters》2023年第10期305-316,共12页纳微快报（英文版）

基　　金：supported by the National Natural Science Foundation of China (21975028, U21A20172 and 22011540377);the Special Key Projects (2022-JCJQ-ZD-224-12)。

摘　　要：To achieve high power conversion efficiency(PCE) and long-term stability of perovskite solar cells(PSCs), a hole transport layer(HTL) with persistently high conductivity, good moisture/oxygen barrier ability, and adequate passivation capability is important. To achieve enough conductivity and effective hole extraction, spiro-OMe TAD, one of the most frequently used HTL in optoelectronic devices, often needs chemical doping with a lithium compound(LiTFSI). However, the lithium salt dopant induces crystallization and has a negative impact on the performance and lifetime of the device due to its hygroscopic nature. Here, we provide an easy method for creating a gel by mixing a natural small molecule additive(thioctic acid, TA) with spiro-OMe TAD. We discover that gelation effectively improves the compactness of resultant HTL and prevents moisture and oxygen infiltration. Moreover, the gelation of HTL improves not only the conductivity of spiro-OMe TAD, but also the operational robustness of the devices in the atmospheric environment. In addition, TA passivates the perovskite defects and facilitates the charge transfer from the perovskite layer to HTL. As a consequence, the optimized PSCs based on the gelated HTL exhibit an improved PCE(22.52%) with excellent device stability.

关 键 词：Perovskite solar cell Hole transport layer GELATION Humidity stability Aggregation of LiTFSI 

分 类 号：TM914.4[电气工程—电力电子与电力传动]