2D Orthogonal Composition‐Gradient Perovskite Photodetection Chip for Computational Spectrometry and Imaging

ABSTRACT Miniaturized computational spectrometers are highly desired for intelligent sensing and imaging, which require both a high‐spatial‐resolution photodetector array in hardware and an accurate spectral reconstruction algorithm in software. Herein, we design a space‐confined anion exchange strategy to construct continuous in‐plane composition‐gradient perovskite films along two orthogonal directions, enabling a continuously gradual shift of the bandgap across the entire visible spectrum. The resulting 2D composition‐gradient films were directly integrated with orthogonal top and bottom electrode arrays without additional material transfer to construct a compact filter‐free microspectrometer with 25 × 10 photodetection units. The device exhibits spatially variant spectral responses across the 2D plane. For the high‐dimensional response data acquired from this 2D detector array, a customized segment‐optimized adaptive reconstruction algorithm is proposed, which enables accurate spectral reconstruction with an average root‐mean‐square error of 0.0372 and a spectral resolution as low as 0.8 nm. Additionally, the device supports multispectral imaging, further highlighting its potential for integrated spectral sensing platforms. This work demonstrates a facile strategy for fabricating 2D composition‐gradient materials and offers a promising pathway toward low‐cost, integrable chip‐scale spectral sensing and imaging systems.