Inkjet-printed conductive polymer films for optoelectronic devices

Poly(3, 4-ethylened ioxythiophene): poly(styrene sulfonicacid)(PEDOT:PSS) has been widely investigated as transparent conductive films due to its superior conductivity and transmittance. Films made from PEDOT:PSS have high optical transparency and excellent electrical conductivity; therefore they can be directly used as transparent electrodes or hole transport layers for organic photovoltaics(OPVs), organic field effect transistors(OFETs), organic light-emitting diodes(OLEDs), etc. Owing to the superior optoelectronic performance and excellent flexibility, they are promising alternative candidates for indium tin oxide(ITO) transparent electrodes. Spin coating is a ubiquitous method for film formation because of the facility and simplicity. However, wastage of raw materials and difficulty in large-area patterning severely restrict the extensive application of spin coating in film preparation. In contrast, inkjet printing is currently the most promising technology for the film forming due to its unique advantages, such as solution-processibility, material saving, low cost and compatibility with roll-to-roll technique. Furthermore, it is capable of rapidly and efficiently preparing large-area thin films with various patterns on different substrates, holding great promise in organic electronics especially for flexible electronic devices. This review summarizes recent advances in depositing PEDOT:PSS films via inkjet printing, and discusses further the prospects and challenges posed in this research field.