Nanostructured α-MoO3 thin film as a highly selective TMA sensor

•Room temperature based TMA sensor using α-MoO3 thin film is reported.•Spray deposited α-MoO3 films shows rectangular nanocrystallites on the surface.•The TMA response for 0.5 ppm in 54% RH was found to be 12%.•Response and recovery time of the film for 0.5 ppm was found to be 32 s and 15 s.

Molybdenum trioxide thin films of different thicknesses were prepared on a glass substrate with the chemical spray pyrolysis technique. The X-ray diffraction pattern indicates the formation of an α-MoO3 phase with a polycrystalline nature. The field-emission scanning electron micrograph of the surface indicates nanostructured lamellar crystallites. The trimethylamine vapour sensing property of the film was studied by the chemiresistive method at room temperature (≈30 °C). Film with a thickness of 520 nm shows a response of 12% for 0.5 ppm of TMA vapour in 54% relative humidity, with response and recovery times of 32 s and 15 s, respectively. The detection limit and sensing response of the α-MoO3 thin film in a mixed environment were analysed and reported.