Organic Semiconductor Heterojunction-Based Photonic Synaptic Transistor with Temperature Stability and Adaptive Learning Ability for Neuromorphic Computing Systems

Photonic synaptic transistors have attracted considerable interest in neuromorphic computing due to their fast response times, low power consumption, and ability to mimic synaptic plasticity when exposed to light stimuli. However, maintaining temperature stability is critical for expanding their practical applications, as temperature fluctuations can degrade their performance and hinder learning capabilities. While some progress has been made in improving temperature stability, current devices still face challenges such as thermal effects leading to performance degradation and reduced learning efficiency. In this work, we present a temperature-stable photonic synaptic transistor based on a heterojunction of N, N ′-bis(salicylidene)-1,3-propanediamine (NSP) and pentacene. Combining the thermal resilience and strong light absorption of NSP with the high mobility of pentacene, this design achieves good field effect and positive photomemory properties. Notably, due to the photoinduced charge transfer within the heterojunction, the transistor demonstrates excellent synaptic performance, particularly with maximum photoresponsivity and dynamic range under 435 nm light. The device maintains stable synaptic behavior across a wide temperature range of 20 to 120 °C, allowing for adaptive learning under varying temperatures, which contributes to the comprehensive processing behavior of visual and thermal sensation. This work demonstrates the potential of organic heterojunctions to enhance device performance and provides valuable insights into developing temperature-resilient neuromorphic devices.