Improving the Electrical Properties and Hole Extraction Efficiency of Inverted Perovskite Solar Cells with AuCl3 Interfacial Modification Layer

Abstract

Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been widely used in inverted perovskite solar cells (PSCs) due to its simple preparation process and high stability. However, because of its low conductivity and charge transfer ability, the power conversion efficiency (PCE) of inverted device is poor. To solve this problem, AuCl3 is introduced to modify the interface between the hole transport layer (PEDOT:PSS) and electrode (ITO). The X‐ray photoelectron spectroscopy (XPS) spectra of PEDOT:PSS confirms that the PSS chains are reduced and the conductivity are increased after AuCl3 doping. Moreover, AuCl3‐modified PEDOT:PSS is beneficial to guide crystal growth and to improve the grain size, crystallinity, and water contact angle of perovskite films. Meanwhile, the defects of PEDOT:PSS/perovskite interface are effectively passivated, which suppresses the nonradiative recombination. The hole extraction efficiency is improved from 8.88× to 1.31× s−1. As a result, the short‐current density (Jsc) and fill factor (FF) are improved, which leads to a champion device with PCE up to 18.08%, much higher than 16.03% of pristine one. The unencapsulated device remains 80% of the initial efficiency after 4 weeks under 45 ± 5% humidity. The results provide a new strategy for synergistically enhancing the efficiency and stability of PSCs by interfacial modification and doping.