Photoelectric Synaptic Plasticity Realized by 2D Perovskite

Recently, several light-stimulated artificial synaptic devices have been proposed to mimic photonic synaptic plasticity for neuromorphic computing. Here, the photoelectric synaptic plasticity based on 2D lead-free perovskite ((PEA)₂SnI₄) is demonstrated. The devices show a photocurrent activation in response to a light stimulus in a neuron-like way and exhibit several essential synaptic functions such as short-term plasticity (STP) and long-term plasticity (LTP) as well as their transmission based on spike frequency control. The strength of synaptic connectivity can be effectively modulated by the duration, irradiance, and wavelength of light spikes. The ternary structure of (PEA)₂SnI₄ causes it to possess varied photoelectric properties by composition control, which enhances the complexity and freedoms required by neuromorphic computing. The physical mechanisms of the memory effect are attributed to two distinct lifetimes of photogenerated carrier trapping/detrapping processes modulated by controlling the proportion of Sn vacancies. This work demonstrates the great potential of (PEA)₂SnI₄ as a platform to develop future multifunctional artificial neuromorphic systems.