Thiophene-Based Two-Dimensional Dion–Jacobson Perovskite Solar Cells with over 15% Efficiency

Abstract

Two-dimensional (2D) perovskites are emerging photovoltaic materials because of their highly tunable photophysical proper-ties and improved environmental stability in comparison with 3D perovskites. Here, a thiophene-based bulky dication spacer, namely 2,5-thiophenedimethylammonium (ThDMA), was developed and applicated in 2D Dion–Jacobson (DJ) perovskite. High quality 2D DJ perovskite, (ThDMA)MAn-1PbnI3n+1 (nominal n = 5), with improved crystallinity, preferred vertical orienta-tion and enlarged spatially resolved carrier lifetime could be achieved by one-step method using mixed solvent of DMF/DMSO (v:v, 9:1). The optimized device exhibits a high efficiency of 15.75%, which is a record for aromatic spacer-based 2D DJ perov-skite solar cells (PSCs). Moreover, the unencapsulated 2D DJ perovskite devices sustained over 95% of its original efficiency after storage in N2 for 1655 h. Importantly, both the light soaking stability and thermal stability (T = 80 oC) of the 2D DJ perovksite devices are dramatically improved in comparison with their 3D counterparts. These results indicate that highly effi-cient and stable 2D DJ PSCs could be achieved by developing thiophene-based aromatic spacers as well as device engineering.