Ultrasensitive and rapid Detection of LPG Below Sub-LEL Using MoTe₂ Thin Films: A Room Temperature Approach

Liquefied petroleum gas (LPG) plays a vital role in both domestic and industrial sectors; however, it poses serious safety risks due to accidental leakages arising from process malfunctions or human error. Therefore, the development of efficient sensors for reliable LPG detection is of critical importance. In the present study, a highly responsive and cost-effective liquefied petroleum gas (LPG) sensor operating at room temperature was developed using MoTe₂ thin films. MoTe₂ was synthesized through a low-cost hydrothermal route, and thin films were fabricated via the spin-coating technique. The prepared samples were thoroughly characterized to investigate their elemental composition, crystal structure, phase formation, and morphology using EDS, XRD, TEM, SEM, Raman, and FTIR spectroscopy. According to the results, PXRD and Raman spectroscopy suggest a pure phase of hexagonal 2H-MoTe₂. FTIR revealed the presence of Mo-Te vibrational modes. FE-SEM revealed elongated sheet-like structures. The EDX confirms the coexistence of the Mo and Te elements, while colour mapping confirmed the uniform distribution of Mo and Te. Further, the gas-sensing performance of the MoTe₂ thin film was examined toward LPG concentrations in the sub-LEL range (0.5–2.0 vol%). A maximum sensor response of 137 was achieved at 2.0 vol%, while the fastest response and recovery times were 8 s and 22 s, respectively, at 0.5 vol% LPG.