Implementation of Photosynaptic and Electrical Memory Functions in Organic Nano‐Floating‐Gate Transistors via a Perovskite‐Nanocrystal‐Based Nanocomposite Tunneling Layer

Abstract

An organic nano‐floating‐gate transistor (ONFGT) with both photosynaptic and electrical memory functions is developed using a perovskite (CsPbBr3) NC‐insulating polymer (polystyrene; PS) nanocomposite and CsPbBr3 NCs as the tunneling and floating gate layers, respectively. The introduction of the CsPbBr3 NCs–PS nanocomposite layer improves the photoresponsivity of the ONFGT under ultraviolet–visible irradiation, resulting in an increase in both the photocurrent and the light‐to‐dark current ratio by 10−8 A and 104 orders of magnitude, respectively. It also exhibits high responsivity (0.804 A W−1) and external quantum efficiency (249.3%) under 400 nm irradiation. Furthermore, the photosynaptic characteristics of the ONFGT under visible‐light irradiation are investigated. To mimic biological nervous systems, the photocurrent of the device is dynamically modulated by varying the light intensity and duration. Notably, an increase in synaptic weight is observed under repeated photonic stimulations, as shown by changes in synaptic weight with each light pulse. Also, the ONFGT exhibits excellent nonvolatile memory characteristics in the dark, displaying a hysteresis window value of 2.9 V for a gate double sweep under ±5.0 V. Consequently, the perovskite NCs–insulating polymer nanocomposite tunneling layer is crucial for enabling photoresponsivity and memory characteristics in nano‐floating‐gate transistors, making them suitable for multifunctional electronic devices.

Recent progress of organic artificial synapses in biomimetic sensory neural systems

“…5(a), Moon et al employed a PS-CsPbBrNCs nanocomposite and CsPbBrNCs as the tunnel layer and floating gate layer, respectively, to create an organic nano-floating-gate transistor featuring both visual synaptic and electrical storage functionalities. 118 As shown in Fig. 5(b) and (c), ONFGT reached dynamic modulation of synaptic weight by adjusting the intensity and duration of ultraviolet light.…”

“…5(b) and (c), ONFGT reached dynamic modulation of synaptic weight by adjusting the intensity and duration of ultraviolet light. 118 As shown in Fig. 5(d), Chen et al reported a high-performance electrically stimulated long afterglow organic light-emitting transistor with a nano floating gate structure.…”