Tetrachromatic photonic synaptic arrays using WS ₂ monolayers for bioinspired neuromorphic retinas

Artificial tetrachromatic vision significantly enhanced color discrimination by enabling the detection and spectral decoding of ultraviolet (UV) and visible wavelengths. Inspired by the butterfly visual system, we develop a tetrachromatic optoelectronic synapse utilizing monolayer WS₂ as the core element, effectively integrating sensing, memory and processing capabilities. The constructed device demonstrates wavelength-sensitive synaptic excitatory behaviors under both visible and UV stimuli, successfully emulating key synaptic functions including short-term potentiation (STP), long-term potentiation (LTP), and long-term depression (LTD), which achieves an ultralow power consumption of 2.28 aJ. An 8 × 8 retinal synapse array was constructed to achieve high-fidelity tetrachromatic image sensing and memory while enabling color discrimination. Furthermore, the image preprocessing is realized in the optoelectronic synapse array based on visual attention for color, which resulted in an enhancement of the recognition accuracy of the tetrachromatic image to over ~98%. This work endeavor has precipitated to the development of next-generation neuromorphic vision systems that require UV-visible spectral intelligence.