Room-temperature-prepared perovskite/Si photodetector with controllable spectral modulation and encrypted optical...

Encrypted optical communication technology has broad application prospects in modern communication networks, as it addresses the risks of eavesdropping and interference during open-channel transmission. Among various physical-layer encryption methods, the multispectral combination approach exponentially increased the difficulty of decryption and extended the key dimension into multidimensional space. However, this often required the deployment of composite equipment, which contradicted the principles of miniaturization, integration, and intelligence. In this study, we reported a self-powered, room-temperature-processed perovskite/Si photodetector, in which the spectral response range was tuned by controlling the thicknesses of the perovskite layer and the SiO₂ interfacial layer. Unlike conventional approaches, spectral modulation was realized through the SiO₂ layer generated by ultraviolet ozone treatment without solvents, rather than through the perovskite top layer. This method enabled the fabrication of array devices in microregions using mature processes without affecting adjacent areas. Finally, we designed encrypted optical communication systems based on the differential response of signal-receiving array devices, where the intensity and wavelength of light were freely combined, thereby significantly increasing decryption difficulty.