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Self-Organization of PEDOT:PSS Induced by Green and Water-Soluble Organic Molecules

Yıldırım, Erol
Zhu, Qiang
Wu, Gang
Tan, Teck Leong
Xu, Jianwei
Yang, Shuo-Wang
Water-soluble poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most prominent commercial polymer used in photovoltaic cells and thermoelectric devices. Experimental studies in the last decade have shown that it is possible to enhance the low electrical conductivity of PEDOT:PSS by solvent treatment, either in-solution or by post-treatment methods. The origin and mechanism of electrical conductivity improvement varied according to different experimental studies. We had recently shown that phase separation of PEDOT:PSS is key to the electrical conductivity enhancement, where dissolution of insulating PSS shell results in the release of conducting PEDOT grains for aggregation. In this study, we demonstrated that dimethyl sulfone (DMSO2), which is a nontoxic, water-soluble, edible organic molecule, can be a greener alternative to the widely used dimethyl sulfoxide for solvent treatment of PEDOT:PSS chains, via a combined experimental and multiscale molecular modeling approaches. Moreover, crystalline DMSO2 nanowire surfaces that remain in the PEDOT:PSS films act as a template for the self-alignment of PEDOT chains that enhance the electrical conductivity further.