Effective Approaches to Improve the Electrical Conductivity of PEDOT:PSS: A Review

The rapid development of novel organic technologies has led to significant applications of the organic electronic devices such as light‐emitting diodes, solar cells, and field‐effect transistors. There is a great need for conducting polymers with high conductivity and transparency to act as the charge transport layer or electrical interconnect in organic devices. Poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonic acid) (PEDOT:PSS), well‐known as the most remarkable conducting polymer, has this role owing to its good film‐forming properties, high transparency, tunable conductivity, and excellent thermal stability. In this Review, various of interesting physical and chemical approaches that can effectively improve the electrical conductivity of PEDOT:PSS are summarized, focusing especially on the mechanism of the conductivity enhancement as well as applications of PEDOT:PSS films. Prospects for future research efforts are also provided. It is expected that PEDOT:PSS films with high conductivity and transparency could be the focus of future organic electronic materials breakthroughs. The effective approaches to improve the electrical conductivity of PEDOT:PSS are summarized, including light and thermal treatment, and a solvent additive and post‐treatment method. The most widely believed conductivity enhancement mechanism of phase separation between PEDOT and PSS is presented. The electrical conductivity enhancement is beneficial for applications such as polymer solar cells and thermoelectric devices.