Large-Sized α-MoO ₃ Layered Single Crystals for Superior No ₂ Gas Sensing

Abstract

Molybdenum trioxide (MoO₃) has attracted considerable research interests due to its unique structural and electronic properties. Herein, we report a monolithic and scalable NO₂ gas sensor based on centimeter-sized single-crystalline α-MoO₃ synthesized via vapor phase transport method. A combination of advanced characterization probes were utilised to study the morphology, composition and crystalline structures of the as-synthesised crystals. At the optimal operating temperature of 100 °C, the centimeter-sized α-MoO₃ single crystal based sensor shows an outstanding sensitivity towards NO₂ with a limit of detection as low as 5 ppb, with simultaneously superior selectivity and reversibility to NO₂. The scalability and the intrinsic sensing response are further demonstrated by microscale sensor devices fabricated on individual exfoliated α-MoO₃ nanoribbons. Our study presents promising opportunities for the development of a high-performance gas sensing platform based on crystalline α-MoO₃ to enable monolithic, scalable and integrable sensing technologies.

Keywords: Cetimeter-Sized, Single Crystalline, Molybdenum Trioxide, Gas Sensor, Nitrogen Dioxide