Hybrid Bacteriorhodopsin/Zinc Oxide Synaptic Photoconductors for Bio-compatible Neuromorphic Devices

Neuromorphic hardware based on artificial synaptic devices has great potential to break the bottleneck of von Neumann architecture, which makes it possible to emulate the working mode of the human brain with low power consumption and high operation efficiency. However, current synaptic devices can barely detect photons and are bio-incompatible for future all-in-one visual perception technology. Here, synaptic photoconductors based on an organic-inorganic hybrid structure, and composed of photosensitive bacteriorhodopsin protein layer and zinc oxide film are reported. The synaptic photoconductors demonstrate tunable synaptic plasticity with the modulation of the light illumination time and power intensity. The working mechanism of the photogating effect induced by the proton pump process of bR protein molecules is further investigated in detail. Assisting with these properties, the imaging memorization and preprocessing function are successfully emulated by the synaptic photoconductors. The prototype photosynaptic devices provide a unique opportunity to realize artificial synapses, enabling neuromorphic hardware.