Oleylamine Halide Enables the Defect Passivation of Tin-Based Perovskite Nanowires for Highly Efficient and Stable Photodetectors

Abstract

Low-toxicity tin-based perovskite have been a hot spot for optoelectronic devices due to its appropriate bandgap and environmentally friendly nature. However, the more defects of tin-based perovskites compared to their lead-based counterparts hinder their performance and stability. Here, this paper presents a defect passivation method by adding oleylamine iodine (OAI) in CsSnI3 nanowires to inhibit the oxidation of Sn2+, fill the vacancies of iodine ions, and protect the CsSnI3 nanowires from the erosion of water and oxygen in air. Finally, highly efficient and stable CsSnI3 perovskite photodetectors (PDs) are obtained. By adding OAI, the dark current of the device is effectively reduced with the Inoise reaching 2.4´10-15 A/Hz1/2, leading to the detectivity D* as high as 2.1´1012 Jones. Besides, the CsSnI3 nanowire PDs show high light stability, and thermal stability at high temperatures. This method provides valuable guidance for the preparation of high-performance and stable tin-based perovskite devices.

Keywords: tin-based, Perovskite, CsSnI3, photodetector