Post-Polymerization Strategy via Dual Site Clicking for Synthesizing Intrinsically Cross-Linkable Semiconducting Polymers

Abstract

Crosslinked organic semiconductors have opened the way for various fabrication techniques in the field of organic electronics owing to their three-dimensional network structure with high solvent resistivity. However, recent efforts to synthesize cross-linkable semiconducting polymers have been limited by their low molecular weights and yields. In this study, this limitation is overcome by a novel post-polymerization strategy. A reagent with a cross-linkable functional group, (3-mercaptopropyl)trimethoxysilane, is attached to a diketopyrrolopyrrole-based donor–acceptor copolymer (DPPTT) via thioesterification and para-fluoro-thiol reaction, modifying two sites simultaneously. This modification preserves the molecular weight and electrical properties of the original polymers. In addition, the use of click chemistry enables high yield (98%) without any purification. The modified DPPTT demonstrated high resistance to organic solvents (80% retention dipped in 1-chlorobenzene for 1 h). Exploiting this benefit, an ultrathin flexible array of 100 organic field-effect transistors fabricated using conventional photolithography showed high-performance reliability. Thus, this study provides a universal strategy to synthesize versatile polymer semiconductors for practical organic electronics.