Postripening Fabrication and Self-Driven Narrowband Photoresponse of Large-Grain, Phase-Pure CsPbBr₃ Films

Halide perovskites have shown high potential for developing self-driven filterless narrowband photodetectors with the advantages of excellent color recognition, low cost, and simple design. Among the various perovskites, all-inorganic perovskites are most promising for optoelectronic devices due to their unmatched thermal stability, but they are often more difficult to be fabricated into a phase-pure form with large grain sizes. Herein, for the first time, a self-driven all-inorganic perovskite narrowband photodetector (PNPD) fabricated by a scalable postripening aerosol–liquid–solid deposition method in ambient conditions is reported. Significantly, simply applying a short thermal stress to a pristine film with heterogeneous phases and small grain sizes triggers Ostwald ripening and leads to more than tenfold enlarged grains of phase-pure CsPbBr₃ with considerably improved optoelectronic properties. The self-driven CsPbBr₃-based all-inorganic PNPD shows a narrowband response, with a peak responsivity of 106.6 mA W⁻¹, specific detectivity of 2.2 × 10¹² Jones at 535 nm, and a narrow full width at half maximum of only 15 nm, placing it among the best of its kind. The PNPD is also fast (t_rise/t_fall = 3.9/3.21 ms) and stable (above 10 000 on/off switches). This work opens the path of tapping all-inorganic perovskites for next-generation optoelectronics with high performance and reliability.