Filter-Free Color Image Sensor Based On Cspbbr3-3nx3n (X = Cl, I) Single Crystals

Narrowband photodetectors are critical for the application of sensors in imaging systems, spectroscopic photodetectors, and optical communication. All-inorganic mixed-halide perovskite (CsPbBr3-3nX3n, 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 (CsPbBr3-3nX3n) 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 CsPbBr3-3nX3n 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 CsPbBr3-3nX3n 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.