Luminescent properties of Y(OH)3: Tb nanopowders synthesized by microwave-assisted hydrothermal method

In the present work, terbium-doped yttrium hydroxide was successfully synthesized by the microwave-assisted hydrothermal method using yttrium nitrate, terbium chloride, and lithium hydroxide as precursors; the study is based on samples with different terbium concentrations. X-ray diffraction indicates a pure hexagonal structure corresponding with the Y(OH)(3) structure, as well as a preferential growth along (110) planes for the Tb-doped samples. FTIR confirms the presence of Y-OH bonds and no adsorbed nitrogen or N-O bonds. SEM images indicate the formation of rods smaller than 1m in length and diameters ranging from 80 to 55nm while TEM images confirm the presence of large areas corresponding to (110) planes. The sample doped at 4at.% presented the maximum photoluminescent intensity, though the sample doped at 2at.% presented the highest values of quantum yield (23.5%). Quantum yield values decay with terbium concentration to a value of 7.89% for the 10at.% concentration, such changes are attributed to a quenching effect and to differences in the photon-extraction efficiency. Photoluminescence decay time values decrease monotonically from 1.133 for the 2at.% sample to 0.453ms for the sample doped at 10at.%, such behavior is attributed to a self-stimulated emission.