Balancing sustainability and performance in ester-incorporated polymers for organic field-effect transistors via physical and chemical blending

The sustainability of organic semiconductors has emerged as a critical challenge for reducing electronic waste, motivating the development of recyclable and degradable conjugated polymers. Incorporating ester linkages into polymer backbones enables depolymerization and repolymerization; however, these nonconjugated units disrupt the π-conjugation and result in severe degradation of charge transport. Here, we address this fundamental trade-off between sustainability and device performance in diketopyrrolopyrrole (DPP)-based organic semiconductors by implementing two complementary strategies: physical blending and chemical blending of fully conjugated and ester-incorporated polymers. In the physical blending strategy, the introduction of only 10 wt.% of a fully conjugated polymer, P(DPP-2T), into TEET- or TET-containing DPP polymers (2T = bithiophene, TEET = thiophene-ester-ethylene-thiophene, and TET = thiophene-ester-thiophene), in which the backbone esters are introduced as cleavable linkages, leads to dramatic enhancements in hole mobility, up to 330-fold and 380-fold, respectively, when compared to the corresponding neat polymer, while retaining 90 wt.% of the ester-containing polymer in the film. By contrast, chemical blending via terpolymerization yields more limited mobility enhancement, as ester segments distributed along the backbone constrain intrachain charge transport, requiring substantially higher DPP-2T content to achieve appreciable electrical performance. Overall, these results demonstrate that physical blending can more efficiently restore charge transport in the ester-incorporated polymers at lower content of the corresponding fully conjugated polymer, while chemical blending requires higher content of conjugated segments to achieve comparable device performance. This work establishes a general framework for designing sustainable organic semiconductors that minimize electronic waste without sacrificing field-effect transistor performance.