CuBr/ZnS heterostructure: A novel 2D material-based sensor with superior sensitivity and selectivity for environmental toxic NO2 gas

초록

A novel heterostructure CuBr/ZnS sensor with high sensitivity and selectivity, fast recovery time, and strong adsorption energy for environmental harmful NO2 gas has been described in our research study. Density functional theory (DFT + U) and Grimme's DFT-D3 approach is used to accurately account for long-range van der Waals interactions and to investigate all potential sites for the NO2 molecule on the CuBr and ZnS surfaces of heterostructure (CuBr/ZnS). To comprehend the impact of paramagnetic NO2 adsorption on the CuBr/ZnS surface, spin-polarized band structure, and density of states are computed, which revealed that adsorption leads to clear modifications in the electronic characteristics of the material, driven by the orbital contributions of the NO2 molecule. Bader charge analyses and charge density difference maps helped to understand the charge transfer between the NO2 and CuBr/ZnS. The NO2 sensitivity and selectivity is also confirmed by changes in computed work function and conductivity to comprehend the functionality of our produced sensor. The calculated recovery time at room temperature (300 K) is observed short, supporting efficient sensor reusability under ambient conditions. In addition, a comparative study with other interfering gas molecules (such as CO, CO2, H2S, and H2) revealed noticeably lower adsorption energies and minimal electronic modulation, further validating the high sensitivity and strong selectivity of the CuBr/ZnS heterostructure toward NO2. Overall, these results establish CuBr/ZnS as a promising candidate for NO2 detection, offering high sensitivity, strong selectivity, and rapid recovery time which is suitable for practical gas sensing application.

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