Molecular ferroelectric self-assembled interlayer for efficient perovskite solar cells
Chang Xu, Pengjie Hang, Chenxia Kan, Xiangwei Guo, Xian‐Jiang Song, Chenran Xu, Guofeng You, Wei‐Qiang Liao, Haiming Zhu, Da‐Wei Wang, Qi Chen, Zijian Hong, Ren‐Gen Xiong, Xuegong Yu, Lijian Zuo, Hongzheng Chen
Abstract
The interfacial molecular dipole enhances the photovoltaic performance of perovskite solar cells (PSCs) by facilitating improved charge extraction. However, conventional self-assembled monolayers (SAMs) face challenges like inadequate interface coverage and weak dipole interactions. Herein, we develop a strategy using a self-assembled ferroelectric layer to modify the interfacial properties of PSCs. Specifically, we employ 1-adamantanamine hydroiodide (ADAI) to establish robust chemical interactions and create a dipole layer over the perovskite. The oriented molecular packing and spontaneous polarity of ferroelectric ADAI generate a substantial interfacial dipole, adjusting band bending at the anode, reducing band misalignment, and suppressing charge recombination. Consequently, our formamidinium lead iodide-based conventional PSC achieves efficiencies of 25.13% (0.06 cm2) and 23.5% (1.00 cm2) while exhibiting enhanced stability. Notably, we demonstrate an impressive efficiency of 25.59% (certified at 25.36%) in a 0.06 cm2 area for the inverted champion device, showcasing the promise of ferroelectric SAMs for PSCs performance enhancement. The conventional approach with applying self-assembled monolayer suffers from limited interface coverage and weaker dipole interactions. Here, authors employ ferroelectric molecule to construct a dipole layer, achieving certified efficiency of 25.36% for inverted perovskite solar cells.