Unlocking the potential of organic-inorganic hybrids in microwave gas sensors: Rapid and selective NH3 sensing at room-temperature

Microwave gas sensor (MGS), being as a kind of new-developed sensing device, possesses the ability to resolve the poor stability, imprecise selectivity, slow response speed and other problems plaguing room-temperature gas sensors. However, the nature of gas sensing mechanism of MGS has not yet been revealed, and the sensitive materials currently applied on MGS are relatively unstable and insensitive under high humidity. Here we have for the first time reported a highly sensitive, selective, and stable MGS composed of ultra-narrowband microwave filter transducer and organic-inorganic hybrid sensitive material (multilayered structured polyaniline (PANI)SnO2). Owing to the standout capacity of ammonia (NH3) adsorption, the high resistance to water poisoning, and the efficient tuning of relative permittivity ascribed to p-n (PANI-SnO2) heterojunction, the organic-inorganic hybrid based MGS operating at room-temperature can selectively detect low concentration of NH3 with high sensitivity, fast response speed, and anti-humidity capacity, which has never been reported before. This work develops a new class of microwave sensing functional materials, and demonstrates that the concept in tuning relative permittivity for constructing outstanding performance microwave gas sensor.

Automated summary

In this study, a highly sensitive, selective, and stable microwave gas sensor (MGS) composed of an ultra-narrowband microwave filter transducer and an organic-inorganic hybrid sensitive material (multilayered structured polyaniline (PANI)SnO2) was reported for the first time. The MGS showed the capability to selectively detect low concentration of ammonia (NH3) with high sensitivity, fast response speed, and anti-humidity capacity at room temperature. This work not only develops a new class of microwave sensing functional materials, but also demonstrates the concept of tuning relative permittivity for constructing outstanding performance microwave gas sensor.