Electronic structure modulation and enhanced optical-thermoelectric performance through relativistic band engineering in Eu-doped La2O3 (1.25 %, 2.25 %): Advancing PC-LED technology via GGA+U+SOC analysis

Abstract

The study presents a comprehensive computational investigation of europium (Eu)-doped lanthanum oxide (La₂O₃), focusing on the intricate modifications of electronic, optical, and thermoelectric properties at dopant concentrations of 1.25 % and 2.25 %. Utilizing advanced first-principles calculations through Density Functional Theory (DFT) with generalized gradient approximation, Hubbard-U correction, and spin-orbit coupling (GGA + U + SOC), we systematically explored the quantum mechanical responses and structural transformations induced by precise Eu doping. We discovered that adding europium creates minor change at 1.25 %, however a significant change was observed at 2.25 % doping with respect to optoelectronic and thermoelectric properties. Our measured band gap for pristine La₂O₃ was 3.743 eV, for Eu–La₂O₃ was 2.522 eV and for 2Eu–La₂O₃ was 3.252 eV, where Eu–La₂O₃ shows one atom of Eu doped in La₂O₃ and 2Eu shows 02 atoms of Eu doped in La₂O₃. We also calculated the formation energies which shows that the materials are thermodynamically stable. The results provide critical insights into the fundamental mechanisms of dopant-induced property engineering, offering promising perspectives for advanced phosphor-converted light-emitting diode (PC-LED) technologies and highlighting the intricate relationship between dopant concentration and material performance.