Author(s): Huang, L (Huang, Le); Dong, HF (Dong, Huafeng); Huo, NJ (Huo, Nengjie); Zheng, ZQ (Zheng, Zhaoqiang); Deng, HX (Deng, Hui-Xiong); Zhang, G (Zhang, Gang); Cheng, Y (Cheng, Yuan); Li, JB (Li, Jingbo)

Source: SCIENCE CHINA-MATERIALS DOI: 10.1007/s40843-020-1322-2 Early Access Date: APR 2020

Abstract: Recent years have seen swift increase in the power conversion efficiency of perovskite solar cells (PSCs). Interface engineering is a promising route for further improving the performance of PSCs. Here we perform first-principles calculations to explore the effect of four candidate buffer materials (MACl, MAI, PbCl2 and PbI2) on the electronic structures of the interface between MAPbI(3) absorber and TiO2. We find that MAX (X = Cl, I) as buffer layers will introduce a high electron barrier and enhance the electron-hole recombination. Additionally, MAX does not passivate the surface states well. The conduction band minimum of PbI2 is much lower than that of MAPbI(3) absorber, which significantly limits the band bending of the absorber and open-circuit voltage of solar cells. On the other side, suitable bandedge energy level positions, small lattice mismatch with TiO2 surfaces, and excellent surface passivation make PbCl2 a promising buffer material for absorber/electron-transport-layer interface engineering in PSCs. Our results in this work thus provide deep understanding on the effects of interface engineering with a buffer layer, which shall be useful for improving the performance of PSCs and related optoelectronics.

Accession Number: WOS:000530267400002

ISSN: 2095-8226

eISSN: 2199-4501

Full Text: https://link.springer.com/article/10.1007/s40843-020-1322-2