Lead-Free Perovskite Hemispherical Photodetector for Single-Pixel Imaging Encryption and Trajectory Tracking

Advanced photodetectors with intelligent functions, utilizing high-efficiency optoelectronic conversion and processing, show promise in intelligent imaging, communication, and trajectory recognition. Current research, however, centers on traditional single-function detectors. This study explores lead-free perovskite detectors for single-pixel encrypted imaging and trajectory tracking. By employing a spray-coating technique, hemispherical perovskite photodetectors with exceptional performance have been fabricated. This detector exhibits high responsivity (R, 148 mA W^-1), exceptional sensitivity (specific detectivity (D*): 4.8 × 10¹¹ Jones), rapid response time (tr/td = 15/13 μs), low noise (∼10^-13 AHz^-0.5), and excellent current stability (Q_5.5 = 0.021). By integrating Fourier single-pixel imaging technology, the detector can reconstruct decrypted images with a high signal-to-noise ratio (SNR) from multiple angles (0°-180°). An eight-channel differential pixel array and curved structure enable 98% accurate multidimensional trajectory tracking and color classification. This work pioneers lead-free perovskites in encrypted imaging and trajectory tracking.