The Zn₁₂O₁₂ cluster-assembled nanowires as a highly sensitive and selective gas sensor for NO and NO₂

Motivated by the recent realization of cluster-assembled nanomaterials as gas sensors, first-principles calculations are carried out to explore the stability and electronic properties of Zn₁₂O₁₂ cluster-assembled nanowires and the adsorption behaviors of environmental gases on the Zn₁₂O₁₂-based nanowires, including CO, NO, NO₂, SO₂, NH₃, CH₄, CO₂, O₂ and H₂. Our results indicate that the ultrathin Zn₁₂O₁₂ cluster-assembled nanowires are particularly thermodynamic stable at room temperature. The CO, NO, NO₂, SO₂, and NH₃ molecules are all chemisorbed on the Zn₁₂O₁₂-based nanowires with reasonable adsorption energies, but CH₄, CO₂, O₂ and H₂ molecules are only physically adsorbed on the nanowire. The electronic properties of the Zn₁₂O₁₂-based nanowire present dramatic changes after the adsorption of the NO and NO₂ molecules, especially their electric conductivity and magnetic properties, however, the other molecules adsorption hardly change the electric conductivity of the nanowire. Meanwhile, the recovery time of the nanowire sensor at T = 300 K is estimated at 1.5 μs and 16.7 μs for NO and NO₂ molecules, respectively. Furthermore, the sensitivities of NO and NO₂ are much larger than that of the other molecules. Our results thus conclude that the Zn₁₂O₁₂-based nanowire is a potential candidate for gas sensors with highly sensitivity for NO and NO₂.