Controlled solvent vapour annealing for polymer electronics

Solvent vapour annealing (SVA) is demonstrated as an attractive method to anneal polymer blend and block copolymer thin films at low temperatures. It is especially suitable for organic electronics, where sensitive materials with strong intermolecular interactions are used. We demonstrate the effect of solvent vapour exposure on the film properties of a perylene bisimide acrylate (PPerAcr) side-chain polymer with strong crystallinity at the perylene bisimide moieties. We record the film thickness, light absorption and fluorescence as a function of the relative solvent vapour pressure. At a certain threshold of relative solvent vapour pressure, we observe a disruption of the pi-pi stacking, which is responsible for perylene bisimide crystallisation. This leads to an increase in the polymer-chain mobility and therefore to changes in the film morphology. The results are applied to a film of a donor-acceptor block copolymer carrying PPerAcr segments, and the influence of solvent annealing on the nanoscale morphology is demonstrated.