A highly efficient interface hole transporting tunnel by a bipyridine semiconductor for perovskite solar cells

Herein, we present a D-A-D type organic semiconductor with a bipyridine core for constructing an efficient tunnel between perovskite and a hole transporting layer to obtain high-performance PSCs. This molecule could facilitate the band bending of perovskite to construct energy level alignment. Moreover, its bipyridine core also passivates the uncoordinated Pb2+ defects of perovskite films. Hence, the hole mobility of the hole transporting layer is increased by 7 times, from 1.05 x 10(-4) to 8.36 x 10(-4) cm(2) V-1 s(-1) and the hole defect density is decreased by 41%, from 4.42 x 10(15) to 2.63 x 10(15) cm(-3) after introducing this hole transporting tunnel. As a result, the power conversion efficiency (PCE) of n-i-p structured PSCs increases from 20.2% to 22.4% with improved stability.

Automated summary

In this study, a D-A-D type organic semiconductor with a bipyridine core was introduced to construct an efficient tunnel between perovskite and a hole transporting layer, resulting in improved performance of PSCs. The molecule facilitated band bending of perovskite and passivated uncoordinated Pb2+ defects in perovskite films. As a result, the hole mobility of the hole transporting layer increased, and the hole defect density decreased, leading to increased power conversion efficiency of the PSCs.