First-Principles Investigation of Sr2PrSbO6 Double Perovskite: An Emerging Aspirant for Electrocatalysis, Plasmonic, Photonics, Thermoelectric and Solar Cell Applications

TL;DR

This work uses first-principles DFT to characterize Sr$_2$PrSbO$_6$ double perovskite, revealing a stable cubic $Fm\overline{3}m$ structure with a lattice parameter of $a=4.267$ Å and a negative formation energy $\Delta E_{formation} = -22.7698$ eV per formula unit, indicating strong thermodynamic stability. It identifies a direct wide bandgap of $E_g = 3.488$ eV at $\Gamma$, non-magnetic ground state, and a valence/Conduction character dominated by O $2p$ and Sb $5d$ states, respectively, with Pr $4f$ states near $E_f$. Optical analysis shows UV-dominated absorption with $\varepsilon_1(0)=2.66$, an onset of $\varepsilon_2$ at $3.52$ eV, and a plasmonic feature near $10.5$ eV, supporting UV optoelectronic and plasmonic applications. Thermoelectrically, $S \approx 1569~\mu$V/K at 300 K and $ZT \approx 0.331$ at 300 K, highlighting potential for PV–TE tandem devices and waste-heat recovery, with further gains anticipated via strain and doping; overall, Sr$_2$PrSbO$_6$ emerges as a multifunctional material for UV photonics, thermoelectrics, and catalysis, warranting experimental validation.

Abstract

In this study, we investigate the structural properties, chemical stability, and electronic, optical, and thermoelectric properties of $\mathrm{Sr_2PrSbO_6}$ using first-principles calculations based on Density Functional Theory (DFT). The goal of this study is to evaluate its potential contribution to next-generation electrocatalysts, optoelectronic devices, and thermoelectric systems. The structural optimization reveals that $\mathrm{Sr_2PrSbO_6}$ crystallizes in a stable cubic perovskite structure with space group $Fm\bar{3}m$. The calculated formation energy indicates high thermodynamic stability, confirming the viability of $\mathrm{Sr_2PrSbO_6}$ for practical applications. The electronic band structure calculations show that $\mathrm{Sr_2PrSbO_6}$ is a wide bandgap semiconductor with a direct bandgap of $3.488~\mathrm{eV}$ at the $Γ$-point. The calculated density of states (DOS) indicates significant contributions from O $2p$, Sb $5p$, and Pr $5d$ orbitals. Optical property calculations, including the dielectric function and absorption coefficient, reveal strong absorption in the UV regions, making $\mathrm{Sr_2PrSbO_6}$ a promising candidate for optoelectronic applications such as UV light-emitting diodes (LEDs) and photovoltaic-thermoelectric (PV-TE) tandem systems. At room temperature, the calculated dimensionless quantity $ZT$ is $0.33$, which indicates this material as a possible candidate for thermoelectric applications. Our results will serve as a benchmark for future experimental and theoretical research on the properties of this material.

Figures (5)

• Figure 1: Crystal structure of the compound showing the arrangement of Pr (yellow polyhedra), Sb (brown polyhedra), and Sr (green spheres) atoms. The coordination geometry is depicted with oxygen atoms (red spheres), highlighting the connectivity of the polyhedra. The unit cell directions (a, b, and c) are shown in the bottom-left corner for reference.
• Figure 2: Formation energy per atom (eV) for various decomposition reactions of Sr2PrSbO6, labeled by reaction number. Positive formation energy values indicate energetically unfavorable reactions, while negative values correspond to energetically favorable reactions. Reaction 7 exhibits the highest positive formation energy, indicating a strong endothermic process, whereas reactions 1 and 2 display the lowest formation energies, suggesting highly exothermic reactions.
• Figure 3: Spin-polarized electronic properties of Sr2PrSbO6 determined using GGA calculations: (a) Electronic band structure along high-symmetry points in the Brillouin zone, with the Fermi level set to zero; (b) Total and partial density of states (DOS and PDOS), showing contributions from Sr, Pr, Sb, and O atoms. The inset highlights the contributions from individual atomic orbitals.
• Figure 4: Optical properties of Sr2PrSbO6 as a function of photon energy: (a) Real part of the dielectric function; (b) Imaginary part of the dielectric function; (c) Optical absorption spectrum; (d) Optical reflectivity; (e) Refractive index; (f) Electron energy loss spectrum (EELS). Highlighted regions indicate the energy ranges of interest.
• Figure 5: Variation in the thermoelectric properties of Sr2PrSbO6 as a function of $\mu - E_f$ at different temperatures (300 K, 500 K, 700 K): (a) Seebeck coefficient (S); (b) Electrical conductivity scaled by relaxation time ($\sigma/\tau$); (c) Electronic thermal conductivity scaled by relaxation time ($\kappa_e/\tau$). The dashed vertical line indicates the Fermi level ($E_f$).