Study on SO₂ and Cl₂ sensor application of 2D PbSe based on first principles calculations

In this paper, we use 2D PbSe to design a gas sensor to monitor the presence of SO₂ and Cl₂. We use first principles to verify the feasibility of this material, such as atomic structure, band gap, differential charge density and Bader charge. The results show that 2D PbSe can distinctly adsorb SO₂ and Cl₂. Furthermore, the adsorption of SO₂ and Cl₂ will affect the electronic structure of 2D PbSe, and some electrons in the PbSe are transferred to gas atoms. The band gap of the system after adsorption is smaller than that of the PbSe before adsorption. The band gap of single layer PbSe decreases by 41.92% after SO₂ adsorption and 60.61% after Cl₂ adsorption. The band gap of multi-layer PbSe decreases by 72.97% after SO₂ adsorption and 43.24% after Cl₂ adsorption. This shows that single layer PbSe is more sensitive to Cl₂ and multi-layer PbSe is more sensitive to SO₂. It provides a potential possibility for designing gas sensors for SO₂ and Cl₂ based on 2D PbSe.