Full-Color Pixel with Only a Single Perovskite Photodiode

Photodetectors typically provide only 1D information about light intensity. Even the most basic color sensing requires external optical components, such as integrated filters. This limitation of information richness has only been overcome in recent years at the cost of spatial inefficiencies in multidetector integration designs or challenges in precisely controlling in situ modulation in single-detector designs. Acquiring high-dimensional color information with a single photodetector without external components, integration, or modulation remains a significant challenge that is aimed to resolve in this work. Due to the differences in carrier excitation by photons of varying energies, the simultaneous introduction of both electronic and ionic photoconductivity mechanisms enables the spectral characteristics of the unknown exciting light to be embedded within the impedance features of the device. By extracting impedance spectra and using machine learning-based reconstruction, a full-color pixel is achieved for the first time with just a single photodetector.