Effect of Temperature on Luminescence of LiNbO3 Crystals Single-Doped with Sm3+, Tb3+, or Dy3+ Ions

Abstract

Crystals of LiNbO3 single-doped with Sm3+, Tb3+, or Dy3+ and crystal of LiTaO3 single-doped with Tb3+ were grown by the Czochralski method. Luminescence spectra and decay curves for LiNbO3 samples containing Sm3+ or Dy3+ ions were recorded at different temperatures between 295 and 775 K, whereas those for samples containing Tb3+ ions were recorded at different temperatures between 10 and 300 K. Optical absorption spectra at different temperatures were recorded within the UV-blue region relevant to optical pumping of the samples. It was found that the effect of temperature on experimental luminescence lifetimes consists of the initial temperature-independent stage followed by a steep decrease with the onset at about 700, 600, and 150 K for Sm3+, Dy3+, and Tb3+ ions, respectively. Additionally, comparison of temperature impact on luminescence properties of LiNbO3:Tb3+ and LiTaO3:Tb3+ crystals has been adequately described. Experimental results were interpreted in terms of temperature-dependent charge transfer (CT) transitions within the modified Temperature—Dependent Charge Transfer phenomenological model (TDCT). Disparity of the onset temperatures and their sequence were explained based on the location of familiar zigzag curves connecting the ground state levels of rare earth ions with respect to the band-gap of the host. It was concluded also that LiNbO3:Sm3+ is suitable as an optical sensor within the 500–750 K temperature region whereas LiNbO3:Dy3+ offers the highest sensitivity at lower temperatures between 300 and 400 K.

Highly sensitive optical thermometer of Sm3+, Mn4+ activated LaGaO3 phosphor for the regulated thermal behavior

“…As shown in Figure 3A, the red emission intensity of Mn 4+ ions peaking at 701 nm ( 2 E g → 4 A 2 transitions of Mn 4+ ions) enhances along with an increase concentration of Mn 4+ ions, accompanied by the decline of the orange emission of Sm 3+ ions. The decay time of Sm 3+ ions in Figure S3 is calculated, 26 which decreases monotonously with the increase of Mn 4+ concentration. Figure S4 shows the proposed ET process in LGO: Sm 3+ , Mn 4+ phosphor.…”

Exploring the Impact of Structure-Sensitivity Factors on Thermographic Properties of Dy3+-Doped Oxide Crystals

“…It follows also from Figure 4 that these shortcomings are crucially relevant to the LNO:Dy system. Owing to a strong thermally induced increase of absorption intensity, which we interpret in terms of temperature-dependent charge transfer (CT) transition [42], the absorption bands of Dy 3+ in the UV-blue region disappear in spectra recorded above about 500 K.…”

New Trends in Lithium Niobate: From Bulk to Nanocrystals

“…Luminescence of LiNbO 3 crystals single-doped with various rare-earth ions (Sm 3+ , Dy 3+ or Tb 3+ ) and LiTaO 3 doped only with Tb 3+ was studied in a wide temperature range by Lisiecki et al [11]. Following an initial temperature-independent stage, the luminescence lifetimes showed a steep decrease with increasing temperature with the onset at about 700, 600, and 150 K for Sm 3+ , Dy 3+ , and Tb 3+ ions in LN, respectively, which was interpreted by a phenomenological temperature-dependent charge-transfer model.…”