Structural, Electronic, and mechanical insights into Rb2B’AgBr6 (B’ = Ga, Al, In) double Perovskites: Pathways to Lead-Free optoelectronics

Abstract

This study employs density functional theory (DFT) to investigate the optical, electronic, mechanical, and structural properties of lead-free double perovskites, specifically Rb₂B’AgBr₆ (B’ = Ga, Al, In). The findings indicate that Rb₂B’AgBr₆ compounds exhibit remarkable stability, demonstrated by their highly negative formation energies and favorable mechanical properties, including high ductility and isotropic behavior. Band structure analysis, performed using the modified Becke-Johnson potential, reveals tunable semiconducting behavior. Among the compounds, Rb₂B’AgBr₆with B’ = Ga displays a larger band gap (3.07 eV), making it suitable for UV–visible applications, while the narrower band gap (1.90 eV) observed for B’ = In suggests suitability for infrared optoelectronic applications. So Rb₂AlAgBr₆ has a band gap of 3.07 eV, suitable for UV–visible applications, and Rb₂InAgBr₆, with a 1.90 eV band gap, is suitable for infrared applications.Optical analysis shows strong absorption in the visible spectrum, highlighting the potential of these materials for solar energy devices. These results underscore the promise of Rb₂B’AgBr₆ compounds as lead-free, sustainable alternatives for optoelectronic applications, supporting advancements in green energy technology. Future experimental validation and exploration of dopants could further enhance device performance based on these theoretical insights.

Novelty Statement

This study presents a thorough investigation of the mechanical and optoelectronic properties of Rb₂B’AgBr₆ double perovskites through a DFT framework, distinguishing itself by identifying Rb₂AlAgBr₆ as the most mechanically robust and stable configuration among the studied compounds. The research highlights the unique tunability of the band gap, facilitating targeted applications in both visible and infrared optoelectronics. Additionally, the emphasis on lead-free materials addresses pressing environmental concerns, positioning Rb-based double perovskites as innovative candidates in the quest for sustainable and efficient energy solutions. The comprehensive analysis of structural, electronic, and optical properties offers a foundation for future experimental work and further optimization of these materials in practical applications.