A first principles study of RbSnCl₃ perovskite toward NH₃, SO₂, and NO gas sensing

The sensitivity of a RbSnCl₃ perovskite 2D layer toward NH₃, SO₂, and NO toxic gases has been studied via DFT analysis. The tri-atomic layer of RbSnCl₃ possessed a tetragonal symmetry with a band gap of 1.433 eV. The adsorption energies of RbSnCl₃ for NH₃, SO₂ and NO are -0.09, -0.43, and -0.56 eV respectively with a recovery time ranging from 3.4 × 10^-8 to 3.5 ms. RbSnCl₃ is highly sensitive toward SO₂ and NO compared to NH₃. The adsorption of SO₂ and NO results in a significant structural deformation and a semiconductor-to-metal transition of RbSnCl₃ perovskite. A high absorption coefficient (>10³ cm^-1), excessive optical conductivity (>10¹⁴ s^-1), and a very low reflectivity (<3%) make RbSnCl₃ a potential candidate for numerous optoelectronic applications. A significant shift in optical responses is observed through SO₂ and NO adsorption, which can enable identification of the adsorbed gases. The studied characteristics signify that RbSnCl₃ can be a potential candidate for SO₂ and NO detection.