Cs₂AgInCl₆ Double Perovskite Single Crystals: Parity Forbidden Transitions and Their Application For Sensitive and Fast UV Photodetectors

Abstract

Double perovskite Cs2AgInCl6 is newly reported as a stable and environmentally friendly alternative to lead halide perovskites. However, the fundamental properties of this material remain unexplored. Here, we first produced high-quality Cs2AgInCl6 single crystals (SCs) with a low trap density of 8.6 × 108 cm–3, even lower than the value reported in the best lead halide perovskite SCs. Through systematical optical and electronic characterization, we experimentally verified the existence of the proposed parity-forbidden transition in Cs2AgInCl6 and identified the role of oxygen in controlling its optical properties. Furthermore, sensitive (dectivity of ∼1012 Jones), fast (3 dB bandwidth of 1035 Hz), and stable UV photodetectors were fabricated based on our Cs2AgInCl6 SCs, showcasing their advantages for optoelectronic applications.