End-of-Life usefulness of degradation by products from transient electronics

Abstract Transient electronics, comprising of degradable devices that disintegrate and disappear after their operational life, has received considerable interest in recent years because of the concerns related to the rapidly growing electronic waste (e-waste). However, the degradability or biodegradability of electronic devices alone is insufficient to ascertain environmental safety. The evaluation of the nature of degradation by-products is also essential to assess the environmental impact of a degradable device. Herein, we investigate systematically the hydrolytic degradation by-products of two different types of devices viz. a capacitive pressure sensor and a photodetector, using liquid chromatograph mass spectrometry. The findings reveal that, despite the inherent degradability of constituent materials used in an electronic device, the released by-products can be toxic or could be complex molecules with unknown chemistry such as carcinogenic or contain almost non-degradable polystyrene derivatives/microplastic (e.g., from PEDOT:PSS), or have copper complexes resulting from degraded silk fibroin and poly(ethylene oxide) mass fragments. This analysis underlines the need for careful selection and reassessment of materials employed in transient electronics, as an important factor, to mitigate the end-of-life issues associated with electronics and its environmental impact.