Gao, W. ; Dong, H. ; Sun, N. ; Chao, L. ; Hui, W. ; Wei, Q. ; Li, H. ; Xia, Y. ; Gao, X. ; Xing, G. ; Wu, Z. ; Song, L. ; Müller-Buschbaum, P.MLZ* ; Ran, C. ; Chen, Y.

2022
Elsevier Amsterdam [u.a.]

Abstract: Pb-free Sn-based perovskite solar cells (PSCs) have recently made inspiring progress, and power conversion efficiency (PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial contact between commonly used hole transport layer (i.e., poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS) and FASnI3 film, it is still challenging to effectively extract holes at the interface. Owing to the p-type nature of Sn-based perovskites, the efficient hole extraction is of particular significance to improve the PCE of their solar cells. In this work, for the first time, the role of chiral cations, α-methylbenzylamine (S-/R-/rac-MBA), in promoting hole transportation of FASnI3-based PSCs is demonstrated. The introduction of MBAs is found to form 2D/3D film with low-dimensional structures locating at PEDOT:PSS/FASnI3 interface, which facilitates the energy level alignment and efficient charge transfer at the interface. Importantly, chiral-induced spin selectivity (CISS) effect of R-MBA2SnI4 induced by chiral R-MBA cation is found to further assist the specific interfacial transport of accumulated holes. As a result, R-MBA-based PSCs achieve decent PCE of 10.73% with much suppressed hysteresis and enhanced device stability. This work opens up a new strategy to efficiently promote the interfacial extraction of accumulated charges in working PSCs.

Keyword(s): Energy (1st) ; Soft Condensed Matter (2nd)

1. Heinz Maier-Leibnitz Zentrum (MLZ)

1. No specific instrument