High-entropy oxide optical nanoceramics prepared by thermobaric synthesis

The study presents the synthesis and characterization of high-entropy optical nanoceramics with the composition (Y₀.₂La₀.₂Gd₀.₂Eu₀.₂Er₀.₂)₂O₃, prepared via thermobaric pressing of nanopowders. A comprehensive analysis of the structural and morphological properties, as well as the chemical composition, was performed. Photoluminescence (PL) studies revealed a significant enhancement in the emission intensity of the red spectral range compared to the nanopowder. This enhancement is associated with reduced symmetry around the Eu³ ⁺ ions caused by lattice distortions due to the formation of impurity phases, as well as anionic defects. Optical transmission measurements show that the nanoceramics exhibit transparency of up to 70 % in the visible range, with an optical band gap of 5.77 eV. The increased PL quantum yield, calculated at over 50 % on the basis of measured optical properties, suggests the potential of these nanoceramics as red-emitting materials for optoelectronic applications. The study highlights the influence of configurational entropy and defect engineering on the optical performance of high-entropy oxides, providing a foundation for further exploration in photonic applications.