Quantum Chemical Modeling of CH3NH3MX3 (MAM*X3: M* = Sn, Si, Ge; X = Cl, Br, I) Lead-Free Perovskites in Comparison with Lead-Based Perovskite Materials

Hitler Louis, Tomsmith O. Unimuke, J. Onyinye Ikenyirimba, Gideon E. Mathias, Adedapo S. Adeyinka

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Herein, the theoretical approach with the aid of solid-state density functional theory (DFT) and time-dependent density functional theory (TD-DFT) based codes has been utilized to investigate the structural, electronic, and optoelectronic properties of methyl ammonium MAM*X3 (M* = Sn, Si, Ge; X = Cl, Br, I) lead-free engineered systems. Results elucidated from the structural lattice parameters when Ge, Sn, and Si were doped influences the halides to exhibit unique trend of I > Br > Cl which also reflects the stability of the engineered perovskite. Both Pb-contained and Pb-free organic–inorganic hybrid perovskites (PSCs) exhibit a direct bandgap in the direction of the Г point symmetry for valence band maxima and conduction band minima. The calculated bandgaps for both MAPbX3 and MAM*X3 (M* = Sn, Si, and Ge) are 1.85 eV and 1.42, 1.40, and 1.52 eV, for M* = Sn, 1.24, 1.32, and 1.38 eV for M* = Si, 1.39, 1.22, and 1.43 for M* = Ge respectively, in accordance to halide contribution of the constituent Cl3, I3, and Br3, correlatively. The UV–Vis results obtained from the turbo-lanczos TD-DFT computations explicates that three prominent peaks were evidently observed at different wavelengths of absorption. As such, at 300–350 and 350–380 nm, Sil3 and SiBr3 (CH3NH3SiI3 and CH3NH3SiBr3) modelled perovskite solar cells (PSCs) gave the highest absorbance of 14.0% atomic unit (a.u), depicting a high level of electron excitation upon absorption of ultraviolet rays.

Original languageEnglish
Pages (from-to)2665-2675
Number of pages11
JournalChemistry Africa
Volume6
Issue number5
DOIs
Publication statusPublished - Oct 2023

Keywords

  • DFT
  • Electronic properties
  • Lead-free perovskite
  • Opto-electronic
  • Solar cell

ASJC Scopus subject areas

  • Catalysis
  • Chemistry (miscellaneous)
  • Environmental Chemistry
  • Physical and Theoretical Chemistry

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