Tunable Red-Green Upconversion Luminescence in Novel Transparent Glass Ceramics Containing Er:  NaYF₄ Nanocrystals

Abstract

To develop NaYF(4) as bulk luminescence material, transparent glass ceramics containing Er(3+): NaYF(4) nanocrystals were fabricated for the first time, and the influences of heat-treatment temperature and Er(3+) doping level on their upconversion luminescence were investigated. With increasing heating temperature, the upconversion intensity enhanced accordingly, attributing to the incorporation of more Er(3+) into the grown NaYF(4). Notably, when the heating temperature reached 650 degrees C, the upconversion intensity augmented drastically due to the occurrence of phase transition from the cubic NaYF(4) to the hexagonal one. Interestingly, for the samples heat-treated at 620 degrees C, when the Er(3+) doping level was increased from 0.05 to 2.0 mol %, the upconversion emission was whole-range tunable from monochromatic green to approximately monochromatic red, which could be mainly attributed to the cross-relaxation between Er(3+) ions. The excellent optical properties and its convenient, low-cost synthesis of the present glass ceramic imply that it is an excellent substitution material for the unobtainable bulk NaYF(4) crystal, potentially applicable in many fields.

White light and multicolor emission tuning in triply doped Yb3+/Tm3+/Er3+ novel fluoro-phosphate transparent glass-ceramics

“…Besides, the formation of the cubic a-NaYF 4 at low temperature was previously observed in a uoro-silicate glassceramic and attributed to the metastable character of the glassy state. 35 The X-ray diffraction patterns recorded on the triply doped NYBC-4 glass-ceramics up to 3 h of heat-treatment ( Fig. 3(a)) are identical to those reported in our previous work, suggesting the same crystallization of the cubic uorite-type phase, as further illustrated by the electron microscopy images presented in Fig.…”

Enhancement of upconversion emission in Y3Al5O12:Er3+ induced by Li+ doping at interstitial sites

“…Rare-earth ions doped upconversion (UC) materials have attracted considerable attentions recently for their applications in solid state visible lasers, color displays and biomedical imaging [1][2][3][4]. However, the emissions of most UC materials do not have enough intensity.…”

Nanocrystallisation in oxyfluoride systems: mechanisms of crystallisation and photonic properties

“…Liu et al 205 studied the glass composition 40SiO 2 -25Al 2 O 3 -18NaCO 3 -10YF 3 -7NaF-xErF 3 (x5 0?05, 0?2, 0?5, 1?0, 2?0) (mol-%), in which the main characteristic is the transition from cubic a-NaYF 4 to hexagonal b-NaYF 4 when the temperature increases. bNaYF 4 seems to be more efficient in luminescence processes than the a structure, due to the multisite nature of the Y 3z /RE 3z ions in the hexagonal NaYF 4 crystal.…”