Organic photoconductors sensitive to blue, green, and red light were fabricated using coumarin 6 (C6)-doped poly(m-hexoxyphenyl)phenylsilane (PHPPS), rhodamine 6G (R6G)-doped polymethylphenylsilane (PMPS), and zinc phthalocyanine (ZnPc)/tris-8-hydroxyquinoline aluminum (Alq3) double layer, respectively. Selectivities of the spectral responses of these films were good enough to divide the incident light into three color components, indicating the possibility of color separation without prism for video cameras. The quantum efficiency of a ZnPc/Alq3 double-layer film is over an order of magnitude better than those of C6/PHPPS and R6G/PMPS blend films due to the dissociation of electron–hole pair generated at the interface between ZnPc and Alq3.

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 0 -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.

No abstract

In this paper, we describe a three-layer-stacked color image sensor comprising two organic photoconductive films (OPFs) with thin-film transistor-based readout circuits and a complementary metal–oxide–semiconductor (CMOS) image sensor. In this three-layer-stacked sensor, a blue-sensitive OPF selectively absorbs blue light, a green-sensitive OPF selectively absorbs green light, and a CMOS image sensor (CIS) receives red light. Color video imaging operation at 60 frames per second was confirmed for a prototype sensor having 320 × 240 pixels with a pixel pitch of 20 μm without a color filter array, and good color separation and a linear response of the sensor were achieved owing to the combination of the CIS and color-selective OPFs.

No abstract