Engineering Surface Orientations for Efficient and Stable Hybrid Perovskite Single-Crystal Solar Cells
Chen Yang, Jun Yin, Hong Li, Khulud Almasabi, Luis Gutiérrez‐Arzaluz, Issam Gereige, Jean‐Luc Brédas, Osman M. Bakr, Omar F. Mohammed
Abstract
We synthesized two types of MAPbI3 single-crystal films with dominant (001) and (100) surface orientations for solar cells. We found that both MAPbI3 (001) and (100) single-crystal films have efficient hole transfer into poly(triaryl)amine (PTAA), as evident from the reduced photoluminescence (PL) intensity and lifetime, as well as the type-II energy alignment. Unlike a MAPbI3 (100) single-crystal film with a strong PL quenching due to efficient electron transfer to phenyl-C61-butyric acid methyl ester (PCBM), the MAPbI3 (001) single-crystal film exhibits an increase in PL intensity in the presence of PCBM, which can be attributed to surface passivation. Interestingly, different from the conventional MAPbI3 (100) that suffers from a significant decrease in the PCE (from 19.3 to 14.4%), the MAPbI3 (001) single-crystal film shows an increase in the PCE (from 16.0 to 17.2%) and much better stability under ambient conditions thanks to the dual passivation on the PbI2-rich surface by PCBM and O2.