Photoelectric performance enhancement of Sn-based perovskites by benzylamine boron trifluoride passivation

Abstract

Tin-based halide perovskites have become the prospective photoelectric materials due to their remarkable optoelectronic properties and relatively low toxicity. However, the rapid crystallization and easy oxidation of Sn²⁺ to Sn⁴⁺ made it challenging to fabricate efficient photoelectric devices. Herein, benzylamine boron trifluoride (BBF) was introduced into the FASnI₃ precursor solution to tune the crystal quality and photoelectric properties of FASnI₃ films. It was demonstrated that the BBF passivates the film defects, reduces the content of Sn⁴⁺, enhances the PL intensity and stability, and improves the responsivity at wavelengths from 415 to 980 nm. The treatment of BBF with an optimal concentration of 1.5 mg mL⁻¹ improves the responsivity of the device from 0.89 to 2.6 A W⁻¹. The coordination of BBF with the anions/cations in the perovskite precursor is suggested to account for the improvement of crystal quality and the photoelectric properties of FASnI₃ films.