Composition and Interface Engineering for Efficient and Thermally Stable Pb-Sn Mixed Low-Bandgap Perovskite Solar Cells
Author(s): Chi, D (Chi, Dan); Huang, SH (Huang, Shihua); Zhang, MY (Zhang, Meiying); Mu, SQ (Mu, Shaiqiang); Zhao, Y (Zhao, Yang); Chen, Y (Chen, Yong); You, JB (You, Jingbi)
Source: ADVANCED FUNCTIONAL MATERIALS Volume: 28 Issue: 51 Article Number: 1804603 DOI: 10.1002/adfm.201804603 Published: DEC 19 2018
Abstract: Low bandgap lead-tin (Pb-Sn) mixed perovskite solar cells have achieved high power conversion efficiency in excess of 17%. However, methylammonium (MA) cation is usually contained, and the thermal stability of MA is always a great concern. In this work, according to composition engineering, a nearly formamidinium (FA) based low-bandgap Pb-Sn mixed perovskite FAPb(0.75)Sn(0.25)I(3) is being tried to explore as the absorber layer. Combined with interface engineering by replacing poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS), layer with NiOx as hole transport layer, a power conversion efficiency of 17.25% is obtained. This low-bandgap perovskite solar cell maintains about 91% of its original efficiency at 80 degrees C for 20 h, and 92% of its initial performance after 46 days storage at the room temperature. The good thermal stability of nearly FA based low-bandgap perovskite could be good for delivering efficient and stable perovskite-perovskite tandem solar cells.