Chemical Vapor Deposition for Lead-Free Perovskite-Inspired MA3Bi2I9 Self-Powered Photodetectors .

What is it about?

Lead-free perovskite-inspired materials (PIMs) have attracted great interest in optoelectronics, as they feature electronic properties similar to mainstream lead-based perovskites but are not burdened by the same toxicity issues. However, PIM photodetectors to date have not delivered efficiencies and stability on par with benchmark technologies. With a focus on methylammonium bismuth iodide (MA3Bi2I9)—a prominent lead-free PIM—this study overcomes this challenge by growing the photoactive material through an engineered chemical vapor deposition (CVD) approach. While the commonplace one-tube (1T)-CVD approach delivers films with disconnected grains and large pinholes, a two-tube (2T)-CVD approach is developed that enables the growth of smoother films with superior, compact morphology. The considerable optoelectronic potential of 2T-CVD MA3Bi2I9 films is demonstrated by realizing high-performance self-powered photodetectors, which deliver a responsivity and specific detectivity as high as 0.28 A W–1 and 8.8 × 1012 Jones, respectively, under UV illumination—i.e., approximately twice as large as the 1T-CVD counterparts. Further, nonencapsulated 2T-CVD devices exhibit considerable long-term moisture stability, with an attenuation of their photo response of ≤3% over 100 days. These results demonstrate that 2T-CVD offers a promising platform that can catalyze the development of high-performance lead-free perovskite-inspired optoelectronics.

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Why is it important?

With a focus on methylammonium bismuth iodide (MA3Bi2I9)—a prominent lead-free PIM—this study overcomes this challenge by growing the photoactive material through an engineered chemical vapor deposition (CVD) approach. While the commonplace one-tube (1T)-CVD approach delivers films with disconnected grains and large pinholes, a two-tube (2T)-CVD approach is developed that enables the growth of smoother films with superior, compact morphology.

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