PEDOT and PEDOT:PSS thin-film electrodes: patterning, modification and application in stretchable organic optoelectronic devices

Abstract

Organic optoelectronic devices, such as thin-film transistors, solar cells and light-emitting diodes, have drawn increasing interest because of their promising applications in sensing, energy conversion, optical imaging and optogenetic therapy. With the rapid development of wearable/implantable devices, there is a growing demand for next-generation highly stretchable optoelectronics. Conventional optoelectronic devices are usually constructed based on brittle indium tin oxide electrodes, which cannot meet the needs above, so it is essential to investigate novel electrodes with excellent stretchability. Poly(3,4-ethylenedioxythiophene) (PEDOT) and its aqueous derivative with poly(styrene sulfonate) (PEDOT:PSS) are promising electrode materials for stretchable organic optoelectronic devices considering their low cost, high conductivity, transparency, intrinsic stretchability and solution-processability. However, pure, spin-coated PEDOT-based electrodes typically possess large sizes of at least millimeter level, and it is difficult for them to satisfy the requirements for fabricating high-resolution devices. Therefore, strategies to decrease the feature size of the PEDOT-based electrodes are critically necessary. In this review, we will carefully discuss various patterning strategies for fabricating high-resolution PEDOT and PEDOT:PSS thin-film electrode arrays and summarize their characteristics. Modification methods to further enhance the conductivity and stretchability of PEDOT-based electrodes and their applications in organic optoelectronic devices are highlighted. In the end, the outlook for future research efforts is also described.