Degradable n-Type Organic Semiconductors Based on Knoevenagel Condensation Reaction

The increasing amount of electronic exerts a profound impact on both the environment and human health. Looking forward, it is imperative to develop electronic products that can degrade under mind condition, which largely relies on the development of degradable organic semiconductors (OSCs). Yet, designing degradable OSCs with decent electrical properties is challenging. In this study, two degradable n-type OSCs based on a dynamic covalent C═C bond formed via the Knoevenagel condensation reaction are reported. The cleavage of Knoevenagel formed C═C bond through a retro-Knoevenagel process imparts the degradability of these two OSCs in the weak base, particularly in the human-friendly α-amino acid of lysine. Meanwhile, the C═C bond formed by Knoevenagel reaction preserves optimal backbone planarity and good electron delocalization of the molecules. This, in turn, endows the OSCs with commendable electron transport performance, achieving an electron mobility of up to 0.57 cm² V⁻¹ s⁻¹ in organic thin-film transistors. This work provides a new insight into the molecular design strategy for the development of OSCs with degradability and good electrical properties.