Degradation by design: sequentially degradable organic transistors for sustainable electronics

The growing accumulation of electronic waste (e-waste) and demand for environmentally sustainable technologies have accelerated interest in transient degradable electronics, which physically disintegrate or biodegrade after their functional lifetime. Such devices offer promising pathways towards reducing ecological impact while enabling applications in biomedical implants, environmental sensors, and temporary wearable systems. Biodegradable organic thin-film transistors (OTFTs) play a pivotal role as fundamental building blocks for fully transient electronic circuits, combining mechanical flexibility, solution processability, and controlled disintegration. In this study, we report the development of a fully degradable OTFT fabricated using diketopyrrolopyrrole thiophene-imine-thiophene as the biodegradable semiconducting layer, integrated with a bilayer dielectric composed of poly(vinyl alcohol) (PVA) and poly(caprolactone) (PCL), and a poly(lactic acid) (PLA) substrate. This configuration yields a significant reduction in threshold voltage (VT) from -16.1 to -2 V compared to devices fabricated on octyltrichlorosilane/SiO2, while maintaining comparable charge carrier mobility. The OTFT can be selectively degraded through sequential steps, where the semiconductor dissolves under acidic conditions (1 M HCl), followed by degradation of the dielectric and substrate in basic buffer solution. This controlled disassembly enables separation and potential recycling of individual components, providing a straightforward strategy for environmentally responsible end-of-life management of transient electronics. Overall, this work represents an important step toward realizing low-voltage, fully degradable, and recyclable electronic systems for sustainable applications.