Exploring lead free Rb₂AlInX₆ halide double perovskites for advanced energy harvesting applications

Area of Science:

• Materials Science
• Solid-State Physics
• Computational Chemistry

Background:

• Halide double perovskites are emerging as stable, lead-free alternatives for optoelectronics.
• Limited data exists on their stability, electronic properties, and multifunctionality.

Purpose of the Study:

• To systematically investigate the physical properties of Rb2AlInX6 (X = Cl, Br) using first-principles calculations.
• To assess their potential for optoelectronic and thermoelectric applications.

Main Methods:

• First-principles calculations were employed.
• Structural stability was evaluated using formation enthalpy, tolerance factor, octahedral factor, and octahedral misfit.
• Electronic band structures and mechanical stability (Born criteria, elastic tensors) were analyzed.
• Optical absorption and thermoelectric properties were computed.

Main Results:

• Both Rb2AlInCl6 and Rb2AlInBr6 exhibit structural and mechanical stability.
• They are semiconductors with bandgaps of 2.85 eV (Cl) and 1.90 eV (Br).
• Rb2AlInBr6 shows visible light absorption, while Rb2AlInCl6 absorbs in the near UV.
• Notable thermoelectric power factors were predicted at 800 K.

Conclusions:

• Rb2AlInX6 halides are stable, semiconducting materials with potential for optoelectronic devices, UV photodetection, and thermoelectric applications.
• These findings offer insights into multifunctional halide double perovskites for advanced technologies.