Filter-free color image sensor based on CsPbBr3−3nX3n (X = Cl, I) single crystals

Abstract

Narrowband photodetectors are critical for the application of sensors in imaging systems, spectroscopic photodetectors, and optical communication. All-inorganic mixed-halide perovskite (CsPbBr_3−3nX_3n, X = Cl, I) crystals have emerged as outstanding wavelength-selective light detection materials. They exhibit tunable optoelectronic properties and high stability, and can realize color discrimination without a filter or a bulk spectrometer. This study demonstrates the successful fabrication of a series of centimeter-sized mixed-halide perovskite (CsPbBr_3−3nX_3n) single crystals using the modified Bridgman method. The optical absorption edges of these crystals are continuously tuned from 437 to 664 nm, corresponding to the bandgaps of 2.88–1.90 eV, by changing the halide composition. Subsequently, eight filter-free narrowband photodetectors are fabricated based on the CsPbBr_3−3nX_3n bulk crystals. The narrowband photodetectors exhibit a widely tunable response range from violet to orange, a full-width at half-maximum of <20 nm, and an optimal responsivity of 0.59 A W⁻¹, which demonstrates excellent spectral discrimination capabilities. Finally, a filter-free color image sensor, which is integrated with the CsPbBr_3−3nX_3n narrowband photodetectors, is constructed. The sensor exhibits excellent color and shape recognition abilities. These results demonstrate the exciting potential of the all-inorganic mixed-halide perovskite bulk crystals for the fabrication of compact, high-performance filter-free color image sensors.