Relativistic band gap engineering in Eu-doped Pr2O3: A DFT-based GGA+U+SOC first-principles study to enhance the electronic, optical, and thermoelectric properties for next-generation phosphor-converted LED materials

This study explores the effects of europium (Eu) doping on the optical electronic and thermoelectric properties of praseodymium oxide (Pr₂O₃). Two doping concentrations, 1.25% (Eu-Pr₂O₃) and 2.5% (2Eu-Pr₂O₃), are analyzed using first-principles DFT based calculations with GGA+U+SOC approach. The band gap of pristine Pr₂O₃ decreases from 3.31 eV to 2.54 eV at 1.25% and 2.44 eV at 2.5% Eu doping concentration. Formation energy calculations confirm the thermodynamic stability of all materials. Optical properties analysis shows enhanced ultraviolet absorption and visible transparency, suggesting potential applications in phosphor-converted LEDs (PC-LEDs). Thermoelectric analysis indicates reduced thermal conductivity due to Eu doping, with modest changes in electrical conductivity. The Seebeck coefficient exhibits an n-type to p-type shift based on temperature and doping level, with higher ZT values observed at lower temperatures for single Eu doping.