Ultra-Exclusive Selectivity for the Detection of Formaldehyde in Laser-Induced Zno Mesh Sensor with Few-Nanometer Pores

Abstract

Formaldehyde is classified as a Group 1 biological agent that is "carcinogenic to humans". A gas sensor can be developed to be a chemiresistive device that has a rapid response, outstanding sensitivity, great reproducibility, and excellent selectivity in the detection of formaldehyde. It is a unique pathway to protect human health in formaldehyde-rich environments. To this end, we designed a formaldehyde gas sensor that shows ultra-exclusive selectivity including superior sensing response (over 6,682.8 value to 10 ppm formaldehyde, 1687.6 value for the optimized sensor with reasonable response (2.96 s) and recovery (46.2 s) times) based on a ZnO mesh structure. A laser process enables a ZnO precursor to the mesh structure within 1 min that has few nanometer-sized pores between ZnO crystal domains. The small kinetic size and large dipole moment of formaldehyde can effectively adsorb with good permeability in/on the mesh structure with pores. The generation of sufficient oxygen ion species on the surface of the ZnO crystals also allows the laser-induced ZnO mesh sensor to superior formaldehyde sensing response in an exclusive manner. An excellent sensitivity with a linear correlation of 𝑅2 = 0.999 and considerably stable long-term reliability facilitate making a title of the ultra-exclusive formaldehyde gas sensor based on the ZnO mesh structure. Our work suggests an effective strategy to design a formaldehyde gas sensor that has a huge potential for indoor and outdoor air monitoring.

Keywords: ZnO gas sensor, formaldehyde gas sensor, laser-induced ZnO, ZnO mesh structure, formaldehyde selectivity