Fully inkjet-printed flexible photodetector array for light color detection utilizing carbon nanotubes-organic macrocycles hybrid structures

Color-selective photodetector arrays are essential for imaging, optical communication, and vision systems. Although advances have demonstrated filterless architectures using wavelength-selective materials, most approaches still depend on vacuum-deposition, rigid substrates, or complex multistep fabrication processes, which hinder scalability and compatibility with flexible or wearable platforms. Here, a fully inkjet-printed, flexible photodetector array is demonstrated, enabling wavelength-selective visible-light detection without external filters, vacuum processes, or lithographic patterning. All components, including electrodes, semiconducting channels, and wavelength-selective absorbers, are printed on a substrate using an office inkjet printer under ambient conditions. Multi-walled carbon nanotubes (CNTs) serve as printable electrodes, while semiconducting single-walled CNTs form the active channels. Color selectivity is achieved by integrating three organic macrocycles with distinct absorption bands, spatially patterned using a tri-color ink cartridge. Each of the three photodetectors exhibits a unique photoresponse, enabling the array to resolve the wavelength and intensity of incident light. The devices maintain stable operation under mechanical deformation and after 1000 cycles of repeated illumination. A lightweight neural network model is incorporated into the system to perform real-time spectral classification with high accuracy under varying illumination conditions. This work introduces a scalable, low-cost route to fabricating flexible, color-selective optoelectronic devices entirely through ambient, additive manufacturing.