Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been widely used for electrochemical interfaces. When the surface is covered by an inhomogeneous dielectric layer, ions are injected to the uncovered part of PEDOT:PSS and then laterally diffuse to the covered part. However, this effect has not been incorporated into the device model. Here we show the effect of lateral ionic diffusion on the transient response of electrochemical interfaces. When PEDOT:PSS is partially covered by a dielectric layer, the covered part contributes to the electrochemical admittance unlike metal electrodes. This effect also makes the transient performance of organic electrochemical transistors deviate from conventional models.

聚（3,4-乙撑二氧噻吩）：聚苯乙烯磺酸盐（PEDOT：PSS）已被广泛用于电化学界面。当表面被不均匀的介电层覆盖时，离子被注入到PEDOT：PSS的未覆盖部分，然后横向扩散到被覆盖的部分。但是，此效果尚未合并到设备模型中。在这里，我们显示了横向离子扩散对电化学界面瞬态响应的影响。当PEDOT：PSS被介电层部分覆盖时，与金属电极不同，被覆盖的部分有助于电化学导纳。这种效应也使有机电化学晶体管的瞬态性能偏离了常规模型。