Non-conjugated polymers for improved organic thin film transistors

Blending non-conjugated polymers with organic semiconductors provides a powerful strategy to improve environmental stability, processability, and sustainability in thin-film electronics. Here, we present recent advances using biodegradable and electronically inert polymers as additives or matrices to enhance device performance. First, we show that diketopyrrolopyrrole-based semiconductors (DPP2T) can be effectively blended with biodegradable polycaprolactone (PCL) and polylactic acid (PLA), allowing up to 70% reduction in active material content. Optimized blends (30 wt% DPP2T in PLA:PCL 56:14) maintained high mobility (0.18 cm²V^-1s^-1), low threshold voltage, and on/off ratios near 10⁶, demonstrating that biodegradability need not compromise performance. Second, for n-type semiconductors prone to oxidative degradation, we employed poly(2-vinylpyridine) (P2VP) as a stabilizing additive in blends with P(NDI2ODT2). Even at 0.1 wt%, P2VP enhanced short-term stability, while higher concentrations (10–50 wt%) extended operational lifetime over one week. Finally, we investigated the role of P2VP molecular weight, showing that higher molecular weight additives reduce oxygen diffusion by absorbing moisture, which displaces oxygen and mitigates oxidative degradation. These findings underscore the importance of rationally selecting insulating polymer additives to improve the durability and sustainability of organic electronic devices.