Two Is Better than One: How the Addition of Multiple Biodegradable Polymers Can Improve Organic Thin-Film Transistor Performance

Developing sustainable electronics requires using materials that are either recyclable or biodegradable, without compromising on electrical performance. Here, we introduce a solution-processed biodegradable polymer blend consisting of a diketopyrrolopyrrole-based semiconducting polymer (DPP2T) and different mixtures of two biodegradable polymers, polycaprolactone (PCL) and polylactic acid (PLA). We find that controlling the ratio of components enables a reduction in semiconductor polymer loading (∼70:80% reduction) while maintaining or improving field-effect transistor performance. At a ratio of 30 wt % DPP2T versus 70 wt % PLA and PCL (56:14 ratio), DPP2T self-assembled and crystallized inside the biodegradable polymer matrix, exhibiting a high field-effect mobility (0.18 cm² V^-1 s^-1), a reduced threshold voltage (∼17 V), and a high on/off ratio (∼10⁶). This study demonstrates that performance does not need to be sacrificed for biodegradability.