Understanding the sensing mechanisms of perovskite materials for gases with different properties: a perspective from the oxidation-reduction states of central metal ions

The structural instability and vague sensing mechanisms of perovskite materials when detecting gases with different properties are two main obstacles to the development of novel perovskite gas-sensing materials with high sensitivity and selectivity. The current study firstly simulated the adsorption dynamics of typical reductive, neutral, and oxidative gases on the CsPbBr3 surface and then quantitatively analysed the adsorption energy and charge transfer of gases on the surfaces of the semiconductor. Fundamental reasons for the stability improvement of perovskite materials were ascertained by comparing them with the existing simulation results. More importantly, the sensitivity and selectivity mechanisms of perovskites when sensing different oxidizing and reductive gases were summarized by further exploring the oxidation states of central metal ions and combining output therefrom with the existing experimental data. Finally, the equilibrium between the stability of perovskite materials and the detection sensitivity and selectivity for gases with different oxidation-reduction abilities was evaluated. The study may allow accurate qualitative predictions of the sensitivity and selectivity of various types of perovskite materials for gases with distinct characteristics.