Jongmin Lee, Bum Ho Jeong, Eswaran Kamaraj, Dohyung Kim, Hakjun Kim, Sanghyuk Park*, Hui Joon Park*
|Title||Light-Enhanced Molecular Polarity Enabling Multispectral Color-Cognitive Memristor for Neuromorphic Visual System|
|Volume and page||14, 5775 (2023.09.18)
: [Featured in a Nature Communications Editors’ Highlights: 'Device' section]
: [Featured in various media]
|Year of publication||2023|
Featured in a Nature Communications Editors’ Highlights: 'Device' section
An optoelectronic synapse having a multispectral color-discriminating ability is an essential prerequisite to emulate the human retina for realizing a neuromorphic visual system. Several studies based on the three-terminal transistor architecture have shown its feasibility; however, its implementation with a two-terminal memristor architecture, advantageous to achieving high integration density as a simple crossbar array for an ultra-high-resolution vision chip, remains a challenge. Furthermore, regardless of the architecture, it requires specific material combinations to exhibit the photo-synaptic functionalities, and thus its integration into various systems is limited. Here, we suggest an approach that can universally introduce a color-discriminating synaptic functionality into a two-terminal memristor irrespective of the kinds of switching medium. This is possible by simply introducing the molecular interlayer with long-lasting photo-enhanced dipoles that can adjust the resistance of the memristor at the light-irradiation. We also propose the molecular design principle that can afford this feature. The optoelectronic synapse array having a color-discriminating functionality is confirmed to improve the inference accuracy of the convolutional neural network for the colorful image recognition tasks through a visual pre-processing. Additionally, the wavelength-dependent optoelectronic synapse can also be leveraged in the design of a light-programmable reservoir computing system.