Controlling of the surface energy of the gate dielectric in organic field-effect transistors by polymer blend

In this letter, we demonstrate that by blending insulating polymers, one can fabricate an insulating layer with controllable surface energy for organic field-effect transistors. As a model system, we used copper phthalocyanine evaporated on layers of polymethyl metacrylate blended with polystyrene with different blending ratios and measured the field-effect mobility in transistors. We show that the highest field-effect mobility is achieved for identical surface energies of the dielectric and the semiconductor. This simple technique demonstrates the viability of using the blends of insulating polymers to systematically control the surface energy of the gate dielectric toward achieving better performances.