Phase evolution of KLaF₄ nanocrystals and their effects on the photoluminescence of Nd³⁺ doped transparent oxyfluoride glass-ceramics

Abstract

Quantity of cubic (α-phase) and hexagonal (β-phase) KLaF4 nanocrystals (NCs) tailored by doping.

Structural and optical properties in Tm3+/Tm3+–Yb3+ doped NaLuF4 glass‐ceramics

“…It should be noted that unlike the hexagonal LaF 3 oxyfluoride NCs, 33,39 cubic NaLuF 4 NCs form from each phase-separated droplet, this is typical behavior of alkali lanthanide tetrafluoride NCs. 13,40,41 The size of the NCs is thus similar to the size of the precursor phase-separated F I G U R E 1 (A) XRD patterns for undoped, xTm 3+ -doped (x = 0.1, 0.5 mol%) and 0.5Tm 3+ -yYb 3+ -codoped (y = 1, 2 mol%) GCs. (B) Magnified regions of (111) peak of the corresponding GCs regions, and then they grow more with the adequate heat treatment in temperature and time.…”

“…7,8 Moreover, the controlled crystallization mechanism allows obtaining NCs with sizes up to 50 nm in which the RE ions are incorporated, dismissing the Rayleigh scattering and maintaining the transparency. 9 Glass-ceramics based on LaF 3 , YF 3 , and RLnF 4 (R = K, Na) [10][11][12][13] phases have been described as efficient luminescent materials. In particular, sodium lanthanide tetrafluorides, with the general formula NaLnF 4 , (with Ln = Gd, Y, La, or Lu) have been reported to be ideal hosts for RE 3+ ions that can act as emitting centers and have been widely studied.…”

Glass-Ceramics Processed by Spark Plasma Sintering (SPS) for Optical Applications

“…For the last ten years, the GlaSS group at Ceramics and Glass Institute (CSIC) focused attention on the preparation of transparent glass-ceramics with low-phonon fluoride crystals, such as LaF 3 , NaGdF 4 , NaLuF 4 , KLaF 4 , etc., with rare-earth ions as dopants for optical applications [29,30,[62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78]. The main emphasis was on maximizing the crystalline fraction, maximum incorporation of the RE dopant, and further enhancement in luminescence profile.…”

“…In the case of 0.1 mol% of the Nd 3+ -doped sample, only after heat treatment at 660 • C for times longer than 144 h, β-KLaF 4 nanocrystals were formed. In the case of 0.5 mol% of Nd 3+ -doped sample, β -KLaF 4 nanocrystals were formed only for times longer than 15 h, and the authors concluded that hexagonal nanocrystals needed longer growth times [68].…”

Tunable upconversion emission in NaLuF4–glass-ceramic fibers doped with Er3+ and Yb3+

“…[2][3][4][5][6][7] Higher photoluminescence (PL) efficiencies and better energy-transfer (ET) are usually obtained in OxGCs with respect to glasses due to the controlled crystallization of low phonon-energy uoride nano-crystals (NCs) that are good hosts for Rare-Earth (RE) ions. [8][9][10][11][12][13][14][15][16][17][18] Most glass systems are based on aluminosilicate compositions that show good mechanical, thermal and chemical properties together with improved PL features of uoride NCs doped with RE ions. Most studies were performed on bulk samples but the possibility to prepare GC bers is also becoming a hot-spot for novel optical materials.…”