High-Performance Inverted Perovskite Solar Cells Using Doped Poly(triarylamine) as the Hole Transport Layer

Organolead trihalide perovskite materials have attracted considerable interest because of their successful application in fabricating high-efficiency photovoltaic cells. Charge transport layers play a significant role in improving the efficiency and stability of perovskite solar cells (PSCs). In this work, we investigated the p-type doping effect of the poly(triarylamine) (PTAA) layer on the performance of PSCs by using three dopants. We observe that doping copper(I) thiocyanate (CuSCN) into PTAA led to a higher performance improvement for the PSCs than the use of copper(I) iodide (CuI) or lithium salt (Li-TFSI) as the dopant. The power conversion efficiency (PCE) of the PSCs significantly improved from 14.22% to 18.16% upon doping 2.0 wt % CuSCN with simultaneously enhanced open-circuit voltage, short-circuit current density, and fill factor. The long-term stability of the PSCs was also improved with significantly reduced PCE degradation (from 79% to 25%) after 200 h. Our results provide a simple method to improve the performance of planar PSCs by adding dopants into PTAA.