Conductive channel formation for enhanced electrical conductivity of PEDOT:PSS with high work-function

• Published in: Applied surface science 2020-11, Vol.529, p.147176, Article 147176
• Main Authors: Song, Inho, Yeon Park, Na, Seung Jeong, Gwan, Hwan Kang, Ju, Hwa Seo, Jung, Choi, Jea-Young
• Format: Article
• Language: English
• Subjects: Conductive polymer; Conductivity; Hydroquinone; PEDOT:PSS; Transparent electrode; Work-function
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.147176

[Display omitted] •More than 3-order conductivity enhancement has been achieved for PEDOT:PSS conductive polymer for transparent electrode application.•Unlike conventional approaches, our high conductivity was achieved with simple mixture of additives, hydroquinone (HQ), to PEDOT:PSS solution which can provide enhanced process simplicity and safety by excluding additional or tiresome process for insulator-like PSS removal from coated thin film.•Unlike conventional approaches, our HQ added PEDOT:PSS thin film can maintain its high work function property (98% of pristine PEDOT:PSS) since the conductivity improvement was induced by contiguous conductive PEDOT channel formation within PEDOT:PSS thin film, not by removing PSS which is known to be work function tunable polymer for high work function PEDOT:PSS.•More than 49 of FoM (figure of merit) has been obtained which is criterion indicating commercial viability for transparent electrode (ex. minimum FoM criterion for transparent electrode is 35.) In this study, we report a facile electrical conductivity improvement method for poly (3,4-ethylenedioxythiophene):poly (4-styrenesulfonate) (PEDOT:PSS), which is one of the most widely studied conductive polymers and used for many electronic applications. From our study, we successfully demonstrated that simple hydroquinone (HQ) addition to pristine PEDOT:PSS aqueous solution can dramatically increase the conductivity of PEDOT:PSS thin film from 0.7 S/cm to 1394 S/cm even without removal of an insulator-like PSS from coated PEDOT:PSS thin film. We demonstrated that this superior conductivity enhancement without PSS removal is originated from promoted phase separation between conductive PEDOT and insulating PSS after HQ addition which acts as a proton (H+) donor for PEDOT:PSS. Due to our conductivity enhancement method excluding PSS-removal, high work-function property of PEDOT:PSS is also well preserved which is highly crucial for optoelectronic device application of conductive PEDOT:PSS as a transparent electrode.