HEAT TREATMENT EFFECT ON OPTICAL ABSORPTION AND PHOTOLUMINESCENCE IN Na0.5Bi0.5TiO3 CRYSTALS
Year: 2025
Type: article
Abstract: Optical absorption and photoluminescence spectra of as-grown and heat-treated sodium-bismuth titanate Na0.5Bi0.5TiO3single crystals are studied.The heat treatment was performed in air and vacuum at Tann = 1070 K. Optical absorption and photoluminescence were measured in the spectral range of 1.5 to 3.3 eV.It is found that treatment in air decreases optical absorption, while subsequent treatment in vacuum increases it.Excitation of the as-grown crystal near the edge of the fundamental optical absorption (~2.95 eV) induces intense violet (~2.83 eV) and weak green (~2.25 eV) photoluminescence.Both heat treatment in air and vacuum reduce the intensity of the violet and green photoluminescence bands.The effects of heat treatment on optical absorption and photoluminescence are attributed to electronic transitions in Ti 3+ centers, which compensate for the excess charge of oxygen vacancies and are located within trigonally and tetragonally distorted oxygen octahedra.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4411624545