Cross-linked Polymer-Blend Gate Dielectrics through Thermal Click Chemistry

New cross-linking reagents were synthesized and mixed with polystyrene (PS) in solution to form a blend. Thin-films were spin-coated from the blend and then crosslinked by thermal activation at relatively low temperature (100 degrees C) to form cross-linked gate dielectrics. This new method is compatible with plastic substrates in flexible electronics. The azide and alkyne cross-linking reagents are kinetically stable at room temperature, so any premature cross-linking is avoided during processing. This method also significantly improved the dielectric performances of PS thin films. Solution-processed top-gate organic field-effect transistor devices with indacenodithiophene-benzothiadiazole copolymer as semiconductor layer and the cross-linked PS blend as dielectric layer showed improved performances with lower gate leakages and higher operation stabilities than devices with neat PS film as dielectric layer.