Dual Organic Spacer Cation Quasi‐2D Sn–Pb Perovskite for Solar Cells and Near‐Infrared Photodetectors Application

Tin (Sn)- and Sn-Pb-based perovskites arouse great interests in low-toxicity perovskite. Nevertheless, the instability problems that aroused by Sn oxidation still hinder their applications. To improve the stability of Sn-based perovskite, a relative stable quasi-2D Sn-Pb perovskite is proposed by introducing two mixed organic cations, 2-phenylethylammonium (PEA(+)), and butylammonium (BA(+)), which facilitate both precursor assembly and carrier transportation. As a result, efficient and stable quasi-2D Sn-Pb perovskite solar cells (PSCs) with a power conversion efficiency (PCE) of approximate to 10% and an improved open-circuit voltage ( Voc) of 0.808 V under AM 1.5G illumination are achieved. The maximum power point (MPP) shows that the current of quasi-2D Sn-Pb PSC still maintains 97.7% of original value after 20 000 s. Furthermore, the application of the mixed spacer cation quasi-2D Sn-Pb perovskite in near-infrared (NIR) light detection is demonstrated. Herein, the quasi-2D Sn-Pb perovskite shows a high detectivity of approximate to 6.57 x 10(11) Jones with n-i-p structure under 850 nm. It is suggested in the results that the quasi-2D Sn-Pb perovskite with improved stability holds great potential in infrared photodetection and imaging application.