Control of Phase Separation on Organic Semiconductor/Polymer Blend Field-Effect Transistors

초록

Solvent and polymer matrix effects on the phase separation behaviors of semiconducting oligomer/polymer blends were systematically investigated. Three different acene derivatives as semiconducting oligomers were solution-blended with polystyrene, poly(a-methyl styrene), and poly(triarylamine) (PAA) dissolved in chlorobenzene and tetralin. Optical microscopy, atomic force microscopy, X-ray diffraction analyses were used to characterize these film morphologies and crystal structures. It was found that the microstructure and vertical phase segregation of semiconducting oligomers in the corresponding blend films were strongly affected by the combination of solvent, polymer, and semiconductor. The electrical properties of these blend-based organic field-effect transistors with either bottom gate top contact (BGTC) or top gate bottom contact (TGBC) geometry were consistent with the morphological characterization and most OFETs fabricated from tetralin showed much higher field-effect mobility values than those from chlobenzene. Optimized TGBC OFETs including PAA segregated layers showed the highest mFET value up to 3.0 cm2/Vs.