First Principle Calculation of Lead-Free Inorganic Perovskite ASnI3 using Density Functional Theory (DFT)
Pina Pitriana1, Triati Dewi Kencana Wungu2, Herman3 And Rahmat Hidayat3

1Physics Education Program Study, Faculty of Tarbiyah and Teacher Training, UIN Sunan Gunung Djati Bandung, Jl. A.H Nasution 105, Bandung 40614, Indonesia
2Nuclear Physics and Biophysics Research Division, Physics Study Program, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132, Indonesia
3Physics of Magnetism and Photonics Research Division, Graduate Study Program of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132, Indonesia

Abstract

Lead-based inorganic perovskite crystals currently have great potential to be used as light-absorber material in solar cells, with high energy conversion efficiency. However, the safety issue of lead (Pb) is one of the reasons for developing other materials that are more environment friendly. In this research, optimization of parameter calculation has been done to get electronic structure from ASnI3 including lattice parameter optimization, kinetic cut-off energy, k-point and pseudopotential type using density functional theory (DFT) method. From the results of electronic band structure calculation shows direct bandgap of ASnI3 with band gap energy values from 0.28 eV to 0.47 eV according to cation changes in ASnI3 (A = Li, Na, K, Rb and Cs). In addition, the calculation of projected density of states (PDOS) shows the state density in the valence band ASnI3 is dominated by halides I-5p and Sn-5d, whereas the conduction band is dominated by Sn-5d orbitals and alkali cations (A). The surface charge density of ASnI3 in the crystal plane (110) and (100) shows a strong covalent bond between Sn and I, while the alkaline cations (A) and I show ionic bonds. The number of electrons transferred by the Li cation is more than Cs, which mean Li is more ionic than Cs, it is confirmed using Bader analysis.

Keywords: Perovskite, DFT, ASnI3, band gap energy, charge density, PDOS, Bader analysis

Topic: Physics