Effects of Dielectric Surface Properties on Crystal Structures and Electrical Properties of Organic Semiconductors

초록

There have been many efforts to achieve high-performance organic field-effect transistors (OFETs). One of the key controlling factors is to introduce physicochemically stable and organic-compatible dielectric surfaces, where organic semiconductors tend to grow into highly conjugated active layers. Here, polystyrene (PS)-grafted SiO2 hybrid layers were used as gate dielectrics for TES-ADT based OFETs. Dielectric roughness was controlled by grafting end-functionalized polystyrenes (PSs) to UVO3-treated SiO2 dielectrics. The polymer grafting densities could induce discernible surface roughnesses ranging from 0.2 nm to 1.5 nm. Changes in TES-ADT film microstructure were correlated to changes in the hole mobility of OFETs fabricated on these dielectrics. The primary impact of increased roughness was a decrease in the lateral size of crystal domains. These results confirmed that dielectric roughness is an important technical specification in flexible circuit design and fabrication.