Work

Influence of Interfacial Stress on the Structural Characteristics and Hydrogen Sensing Performance of WO3 Films

Year: 2025

Type: article

Abstract: Tungsten trioxide (WO3) exhibits complementary optical and electrical responses toward hydrogen, yet the interplay between interfacial stress, crystal phase stabilization, and gasochromic/chemiresistive performance remains insufficiently understood. In this work, WO3 films were grown on four single-crystal oxide substrates to systematically tune interfacial stress and thereby modulate the resulting crystal phase, microstructure, and exposed facets. θ–2θ diffraction revealed that WO3 adopts a monoclinic phase on YAlO3 and SrLaAlO4, whereas a high-temperature orthorhombic phase is stabilized on LaAlO3 (LAO) and SrTiO3 due to stronger interfacial constraint. Compared with the amorphous quartz reference, the single-crystal substrates significantly enhanced both gasochromic and chemiresistive responses. In particular, the orthorhombic WO3/LAO film exhibited an electrical response of 1.97 × 104 (Rair/RH2), an optical transmittance changed of 12.7%, and an electrical response time of 1 s toward 2% H2 at 80 °C, far exceeding the monoclinic and amorphous counterparts. The combined effects of stress-induced phase stabilization, film orientation, and hydrogen diffusion pathways are shown to govern the non-monotonic sensing trends among different substrates. These findings elucidate the structural origin of hydrogen sensitivity in WO3 and provide guidance for stress-engineered design of high-performance gasochromic and chemiresistive sensors.

Source: Nanomaterials

DOI: 10.3390/nano15231785