Band structure and absorption spectra of NH4XI3 (X = Pb, Mg) based hybrid Perovskite for UV ray protector and electrochromic materials applications. (April 2021)

• Record Type: Journal Article
• Authors: Agbaoye, Ridwan O.; Adebayo, Gboyega A.; Kenmoe, Stephane
• Is Part Of: Journal of physics and chemistry of solids. Volume 151(2021)
• Publication Date: 2021-04
• Subjects: Bandgaps -- Electronic structure -- Perovskites -- Optical properties -- Absorption coefficient -- Density functional theory -- GW method -- Spin-orbit coupling; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2020.109860
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: Modeling Perovskite materials and tuning their properties by monovalent or divalent cations substitution produce several choice Perovskite compounds, studied extensively to improve the power conversion efficiency, reduce toxicity, and enhance stability. We modeled NH4 PbI3 and NH4 MgI3 from the parent compound CH3 NH3 PbI3, by replacing the monovalent CH3 NH 3 + with NH 4 + and the divalent Pb atom with Mg. In this study, the electronic band structure, as well as the electronic bandgaps, were calculated using the Perdew-Burke-Enzenhoff (PBE) and Perdew-Burke-Enzenhoff for solid (PBEsol) exchange-correlation functionals of the Density-functional Theory (DFT) and GW quasiparticle method of the Many-Body Perturbation Theory (MBPT). Similarly, we used Time-Dependent Density Functional Perturbation Theory (TDDFPT) and the solution of the Bethe-Salpeter equation (BSE) of the Many-Body Perturbation Theory to determine the real and imaginary dielectric tensors with and without spin-orbit coupling (SOC). Direct bandgaps at R high symmetry point were reported for NH4 PbI3, while NH4 MgI3 showed indirect bandgaps at Γ → R high symmetry points with lower bandgaps compared to NH4 PbI3 . The projected density of state around the Fermi level reveals that the iodine (I) p orbital is most responsible for the valence band in both NH4 PbI3 and NH4 MgI3, while the Lead (Pb) p orbital and the Magnesium (Mg) s orbitals, show the most prominent contribution to the Conduction bands. Similar Optical spectra were achieved with BSE-SOC, TDDFPT, and TDDFPT-SOC for NH4 PbI3 without the absorption onsets, while NH4 PbI3 predicts higher values of absorbance and absorption coefficient compared to NH4 MgI3 which predict lower reflectivity and higher transmittance. Both compounds show maximum absorption coefficient in the order of 10 5 in the ultraviolet region like CH3 NH3 PbI3 and silicon. Therefore, we suggest that NH4 PbI3 will be useful as solar cell absorber and UV ray protector, while NH4 MgI3 would have more applications in the production of electrochromic materials. Highlights: AmmoniumLeadIodide Perovskites is a good material for solar cell absorber and ultraviolet ray protector. AmmoniumMagnesiumIodide Perovskite shows good prospect for electrochromic materials. AmmoniumLeadIodide Perovskite shows low transmittance in the ultraviolet region. Absorption coefficient in the order of 10 5 is recorded along the ultraviolet region.