A photo-responsive organic electrochemical transistor

The design of novel organic electrochemical transistor (OECT) channel materials that can be controlled by a whole range of external stimuli is key towards the emergence of unprecedented technologies in bioelectronics. Like the established multiresponsive field-effect transistors, multiresponsive OECTs can in principle be realised via blending, by combining multiple components with each one imparting a specific function to the device. Here we report the first example of an optically switchable OECT which is capable of undergoing a reversible modulation of its ON current by up to 30% upon irradiation with UV and visible light. By investigating the electrical characteristics of the channel material, in conjunction with the electronic characterisation performed by a macroscopic Kelvin probe technique and photoemission yield spectroscopy in air, we gained distinct insight into the electrochemical doping process occurring within the blend upon light irradiation. Such a proof-of-concept work opens perspectives towards the implementation of complex neuromorphic operations and algorithms in OECTs.