Visible-light stimulated synaptic plasticity in amorphous indium−gallium−zinc oxide enabled by monocrystalline double perovskite for high-performance neuromorphic applications

Photoelectric synaptic devices have been considered as one of the key components in artificial neuromorphic systems due to their excellent capability to emulate the functions of visual neurons, such as light perception and image processing. Herein, we demonstrate an optically-stimulated artificial synapse with a clear photoresponse from ultraviolet to visible light, which is established on a novel heterostructure consisting of monocrystalline Cs₂AgBiBr₆ perovskite and indium–gallium–zinc oxide (IGZO) thin film. As compared with pure IGZO, the heterostructure significantly enhances the photoresponse and corresponding synaptic plasticity of the devices, which originate from the superior visible absorption of single-crystal Cs₂AgBiBr₆ and effective interfacial charge transfer from Cs₂AgBiBr₆ to IGZO. A variety of synaptic behaviors are realized on the fabricated thin-film transistors, including excitatory postsynaptic current, paired pulse facilitation, short-term, and long-term plasticity. Furthermore, an artificial neural network is simulated based on the photonic potentiation and electrical depression effects of synaptic devices, and an accuracy rate up to 83.8% ± 1.2% for pattern recognition is achieved. This finding promises a simple and efficient way to construct photoelectric synaptic devices with tunable spectrum for future neuromorphic applications.