Color Sensors with Three Vertically Stacked Organic Photodetectors

A stacked structure composed of three organic photodetectors that were individually sensitive to only one of the primary color components was fabricated based on tetra(4-methoxyphenyl) porphine cobalt complex, NN'-dimethylquinacridone, or zinc phthalocyanine, as blue, green, or red sensitive photoconductive materials, respectively. The spectral photoresponse characteristics were measured, and the output signal from each detector showed good spectral selectivity, clearly demonstrating color separation in the vertically stacked structure. Comparisons of the output signal currents of single structures (without stacking) and the stacked structure revealed that 70% of the incident light reached the bottom layer of the stack.