Application of Perovskite as Solution‐Processed Solid Electrolyte in Polymer Electrochemical Transistor

Abstract The electrolyte serves as a key component in organic electrochemical transistors (OECTs) and allows for the modulation of the conductivity of the polymer channel by applying a voltage to the gate electrode. Different from liquid electrolytes in OECTs, the solid electrolyte is beneficial for the integration in the circuit and shows great stability. And considering the fabrication of the device, developing a new solution‐processed solid electrolyte for OECTs is a critical area of research. In this work, the organic–inorganic perovskite is used as the electrolyte to fabricate polymer electrochemical transistors due to its solid‐phase ion migration kinetics. To realize this goal, a separate polyethylene oxide (PEO) layer on top of the poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) layer plays a crucial role since it can affect the electric field and the ion motion. More importantly, based on this device structure, both a polymer light‐emitting electrochemical transistor and the polymer electrochemical phototransistor are realized. The solution‐processed solid organic–inorganic perovskite electrolytes can enable the development of integration in OECTs, which have significant potential for multifunctional applications.