Enabling robust broad-spectrum photodetection with ultra-high responsivity through vapor growth of 2D all-inorganic lead-free Cs2SnI6 perovskites

The all-inorganic lead-free perovskite Cs 2 SnI 6 has gained considerable research attention due to its outstanding characteristics, including non-toxicity, robust stability, and superior photoelectric performance. In this research, we employed a simple yet robust chemical vapor deposition technique to successfully grow ultra-thin 2D Cs 2 SnI 6 flakes on a mica substrate, achieving a minimal thickness of just 8 nm and a significant lateral size of up to 48 jim. The obtained 2D Cs 2 SnI 6 flakes displayed an extended photoluminescent lifetime of approximately 1.44 ns and exceptional stability, maintaining their crystal structure intact over a period of 60 days. The photodetectors fabricated from Cs 2 SnI 6 flakes demonstrated a broad ultraviolet to near-infrared response range (365 -1342 nm), with a responsivity of up to 6.25 x 10 5 A W -1 . They additionally displayed rapid rise and decay times of 31.32 ms and 72.42 ms, respectively, with an external quantum efficiency reaching as high as 1.92 x 10 6 %, and a detectivity achieving 1.27 x 10 11 Jones. This research serves as a critical step forward in enabling the facile yet robust synthesis of stable, all-inorganic ultra-thin lead-free perovskites, paving the way for innovation in environmentally friendly optoelectronic devices.