Flexible Organic Transistors for Color Recognition and Nature-Inspired Synaptic Function Simulation: Performance and Stability

Pursuit of replicating intricate cognitive functions demands enhanced efficiency, reduced power consumption, and superior parallel computing capabilities, driving the evolution of brain-inspired computing, which has been demonstrated through artificial synaptic devices. Among these, photosensitive organic synaptic transistors (POSTs) emerge as exceptional candidates due to their ability to integrate sensory and computational functionalities under optical stimuli. In this study, flexible POSTs were demonstrated with biocompatible poly(4-vinylpyridine) (PVPyr) as the gate dielectric and 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) as the active layer. These POSTs exhibited high performance, achieving −10 V operation with excellent saturation in output characteristics, a maximum mobility of ∼0.5 cm 2 /(V s), and a current on–off ratio of ∼10 3 for the p-channel operation. Moreover, remarkable operational, electro-mechanical, and environmental stability was observed from these devices, making them suitable for long-term practical applications. Most importantly, the POSTs demonstrated notable color recognition capabilities for both blue and green light, with a maximum photo responsivity of ∼92 mA/W and an external quantum efficiency of ∼25% for blue color. These devices also successfully emulated synaptic behaviors, including pulse-paired facilitation (PPF) and transitions from short-term plasticity (STP) to long-term plasticity (LTP) under visible light stimulation, while their low power consumption enabled responses that closely mimic biological synapses. Our results indicate a significant step toward the development of eco-friendly, high-performance devices for bioinspired artificial sensory systems. The demonstrated dynamic learning capabilities and efficient information storage pave the way for future applications in brain-inspired computing, neuro-prosthetics, and wearable smart technologies.