The Polymer Society of Korea

Abstract

Organic electronic devices offer advantages such as flexibility and low-cost fabrication, but poor air stability limits their sustainability. Here, we report an eco-friendly organic gas sensor based on blended thin films of poly(3-hexylthiophene) (P3HT) and poly(butylene succinate) (PBS). On hydroxyl-rich substrates, PBS migrated to the bottom of the active layer, forming a bilayer structure. In contrast, tuning the substrate surface energy using a hexamethyldisilazane self-assembled monolayer induced a trilayer vertical phase separation, with P3HT selectively located at both the top and bottom of the active layer. The intermediate PBS layer suppressed atmospheric oxidation of P3HT, improving air stability. Notably, despite increased PBS content, device performance was maintained while gas sensing performance was enhanced. These results highlight biodegradable polymer–assisted vertical phase separation as an effective strategy for sustainable organic gas sensors.