Light sensors and opto-logic gates based on organic electrochemical transistors

Abstract

In this study, we combine a photochemical cell with a transistor, forming a novel optical-to-electronic interface using OECTs with a light-sensitive gate, which can be used for photonic, optogenetic and other applications where conversion from an optical to electronic signal is key. The light-sensitive properties of organic electrochemical transistors (OECTs) based on polythiophene and PEDOT:PSS have been studied for the first time. It has been found that the maximum transconductance of a developed OECT shifts to higher gate voltages with the increase of light irradiation at the polythiophene gate electrode. This gate material chosen for the OECT plays an important role in the light-enhanced oxygen reduction reaction (ORR), which is subsequently responsible for the doping/de-doping of the channel material upon light illumination, thus making the OECT an efficient light sensing device. Additionally, the connection of these devices allowed the creation of organic opto-logic gates. This very first low voltage organic optical-to-electronic interface can potentially find applications in modern electronics and photonics. The development process includes geometry optimization and optimization of the channel and gate materials.