인천대학교 인디고클랫폼 인천대학교 기술지원허브

Conjugated polymers are promising sensing materials for portable sensors because of their mechanical flexibility, low mass, and cost-effective processing, which are essential for next-generation devices such as electronic skins. However, despite these advantages, gas sensors based on conjugated polymers remain difficult to commercialize due to their limited gas sensitivity. This study introduces a strategy to enhance sensitivity by forming a porous structure in the poly(3-hexylthiophene) (P3HT) active layer through a simple nonsolvent immersion process, thereby increasing the density of gas-molecule adsorption sites. Among the tested nonsolvents, n-hexane (Ra = 8.6 MPa1/2), which exhibits the smallest solubility distance from P3HT, produced the deepest and widest pore morphology and the highest surface roughness (Rq = 2.98 nm), leading to a maximized effective surface area. As a result, the hexane-treated film exhibited the highest sensitivity to NO₂, achieving an approximately fourfold enhancement compared with the pristine P3HT film. These results demonstrate an effective approach for tuning surface area through a simple processing route and provide a viable surface-engineering strategy for high-performance organic gas sensors.