Combinatorial screening of organic electronic materials: thin film stability

摘要: Dewetting of thin polymeric semiconducting?insulating (and conducting?insulating) bilayers is a serious fundamental problem facing the fabrication organic electronic devices such as transistors, light-emitting diodes and supercapacitors. This paper describes high-throughput characterization method that utilizes orthogonal thickness-gradient libraries bilayer components poly(3-octylthiophene) (semiconductor) poly(styrene) (insulator). The technique allows simultaneous observation hundreds combinations thicknesses has permitted rapid discovery previously-unknown VDW instability transition. We observe onset in PS?P3OT complex function P3OT thickness cannot be predicted by Hamaker constant models for free energy. At low thickness, semiconductor acts to stabilize PS insulator. But above 175 nm, this behaviour switched destabilizes PS. These thickness-dependent effects are correlated very well with dramatic transitions optical spectra P3OT?AFM tip interaction forces. unusual places critical limitations on practical device interfacial combinations, points need thin-film stability theory accounts molecular?electronic effects.