Solvent-Resistant Organic Transistors and Thermally-Stable Organic Photovoltaics Based on Crosslinkable Conjugated Polymers

Conjugated polymers in general are unstable when exposed to air, solvent, or thermal treatment, and these challenges limit their practical applications. Herein we have developed a simple, but powerful approach to achieve solvent-resistant and thermally stable organic electronic devices with improved air-stability, by introducing a crosslinkable group into a conjugated polymer. To demonstrate this concept, we have synthesized polythiophene with crosslinkable groups attached to the end of alkyl chain. Photo-crosslinking of crosslinkable P3HT dramatically improves the solvent resistance of the active layer without disrupting the molecular ordering and charge transport. This is the first demonstration of solvent-resistant organic transistors. Furthermore, the bulk-heterojunction organic photovoltaics (BHJ OPVs) containing crosslinkable P3HT show an average efficiency higher than 3.3{\%} after 40 h annealing at an elevated temperature of 150$^{\circ}$C, which represents one of the most thermally-stable OPV devices reported to date. This enhanced stability is due to an in-situ compatibilizer that forms at the P3HT/PCBM interface and suppresses macrophase separation.