Unsubstituted thiophene–diketopyrrolopyrrole conjugated polymer thin films via oxidative chemical vapor deposition – electronic behavior

Conjugated polymers (CPs) based on diketopyrrolopyrrole (DPP) constitue an important class of high-performance organic semiconductors. While N-alkylation of DPP is required for the solution-based synthesis of DPP-based CPs, oxidative chemical vapour deposition (oCVD) is shown to provide a straightforward solventless and scalable approach for the facile polymerisation of N-unsubstituted DPP. The oCVD reaction of 3,6-di(2-thienyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (TDPP) yields polymer thin films combining H-bonding and conjugated covalent bonds, resulting in a superior conductivity and a systematic increase of the lifetime of electronically excited states compared to N-alkylated counterparts.