Vertically stacked monolithic multiband perovskite photodetectors for color-filter-free imaging

Modern color image sensors face challenges in further improving sensitivity and image quality because of inherent limitations in light utilization efficiency1. A significant factor contributing to these limitations is the use of passive optical filters, which absorb and dissipate a substantial amount of light, thereby reducing the efficiency of light capture2. On the contrary, active optical filtering in Foveon-type vertically stacked architectures still struggles to deliver optimal performance due to their lack of color selectivity, making them inefficient for precise color imaging3. Here, we introduce an innovative architecture for color sensor arrays that employ multilayer monolithically stacked lead halide perovskite thin-film photodetectors. Perovskite bandgap tunability4 is utilized to selectively absorb the visible light spectrum's red, green, and blue regions, eliminating the need for color filters. External quantum efficiencies of 50%, 47%, and 53% are demonstrated for the red, green, and blue channels, as well as color accuracy of 4.5 in ΔELab, outperforming state-of-the-art color-filter array and Foveon-type photosensors. The novel image sensor design improves light utilization in color sensors and paves the way for a new generation of highly sensitive, artifact-free images with enhanced color fidelity.