Porous Glycine-Modified LaFeO3 for Highly Selective Ethanol Sensing: Band Gap Engineering Driven by Organic-Inorganic Hybridization.

The demand for highly selective ethanol sensors for reliable environmental and industrial monitoring remains a critical challenge. Herein, we demonstrate a facile hydrothermal strategy to synthesize porous glycine-LaFeO3 (Gly@LFO) composites, where organic-inorganic hybridization drives significant band gap narrowing. This electronic restructuring, combined with a porous morphology (optimal at a 1:1 Gly-to-LFO ratio, sample L3), creates abundant active sites and facilitates rapid gas diffusion as confirmed by SEM, EDS, and XPS analysis. First-principles calculations elucidate the underlying mechanism, revealing that Gly modification narrows the band gap from 2.19 to 1.59 eV and introduces shallow defect states, which significantly boost carrier concentration and mobility. The L3-based sensor delivers an exceptional response of 701 toward 10 ppm ethanol at 150 °C, representing a 287% enhancement over the pristine LFO sensor, with rapid response/recovery times (7/9 s). The device also exhibits outstanding selectivity, long-term stability (>28 days), and robust humidity resistance. This work presents a synergistic organic-inorganic strategy, offering a robust framework for the rational design of next-generation gas sensors.