Optoelectronic Study of (MA)$_2$NaBiX$_6$ (MA= methylammonium; X=Cl,Br, I) Hybrid Double Perovskites by Ab initio Simulation

TL;DR

This study uses ab initio simulations to analyze the optoelectronic properties of (MA)$_2$NaBiX$_6$ hybrid double perovskites, highlighting the superior potential of the iodide variant for optoelectronic applications.

Contribution

First ab initio investigation of (MA)$_2$NaBiX$_6$ perovskites, revealing their electronic properties and stability for optoelectronic use.

Findings

(MA)$_2$NaBiI$_6$ has the lowest indirect bandgap among the studied compounds.

(MA)$_2$NaBiI$_6$ exhibits high absorption coefficient, dielectric constant, and refractive index.

Iodide-based perovskite shows potential for optoelectronic applications due to its favorable properties.

Abstract

High prospects for different optoelectronic applications have drawn much effort towards hybrid double perovskites for the commercialization of environmentally friendly Pb-free non-toxic perovskites. Herein, the optoelectronic study of (MA)$_2$NaBiX$_6$ (MA= methylammonium; X=Cl,Br, I) hybrid double perovskites by ab initio simulation was investigated. (MA)$_2$NaBiBr$_6$ and (MA)$_2$NaBiCl$_6$ have indirect X-M bandgaps while (MA)$_2$NaBiI$_6$ have indirect X-$\Gamma$ bandgap of 2.98 eV, 3.64 eV and 2.32 eV respectively. The results also show that the iodide-based compound, (MA)$_2$NaBiI$_6$ exhibits superior optoelectronic properties compared to the bromide and chloride-based compounds, (MA)$_2$NaBiBr$_6$ and (MA)$_2$NaBiCl$_6$. These findings indicate that the (MA)$_2$NaBiI$_6$ hybrid double perovskite is a potential material for optoelectronic applications owing to its high absorption coefficient (on the order of 106cm-1), dielectric constant ($\approx 3.34$), and refractive index (2.50) in addition to its high formation energy, which shows its stability.