期刊
MATERIALS TODAY CHEMISTRY
卷 26, 期 -, 页码 -出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.mtchem.2022.101013
关键词
Rare-earth ions; Luminescence; Nanoparticles; White-LEDs; Anti-counterfeiting
资金
- K. C. Wong Magna Fund in Ningbo University
- Fundamental Research Funds for the Provincial Universities of Zhejiang [SJLZ2020004]
- Natural Science Foundation of Zhejiang Province [LQ20F050004]
- Fondo Social Europeo
- Agencia Estatal de Investigacion [RYC2020-028778-I/AEI]
Red-emitting phosphors with concentration quenching and unsatisfied thermal stability can be improved by utilizing phase transition to tailor the properties of Eu3+-activated NaYbF4 nanoparticles. The samples undergo a phase transition from cubic to hexagonal phase with increasing doping level, resulting in enhanced thermal stability and increased optimal doping content. Moreover, the local coordination environment of Eu3+ in the host lattice is changed, further confirmed by theoretical calculations.
Red-emitting phosphors play a vital role in reinforcing the quality of phosphor-converted white light-emitting diodes. Unfortunately, concentration quenching and unsatisfied thermal stability are still the inevitable shortcomings of the red-emitting phosphors. Herein, we utilized phase transition to simultaneously tailor the concentration quenching and thermal stability of Eu3+-activated NaYbF4 (NaYbF4:xEu(3+)) nanoparticles, in order to overcome these limitations. With the increasing doping level, the resultant samples undergo a phase transition from cubic to hexagonal phase. Notably, the optimal doping content for Eu3+ in the NaYbF4 nanoparticles with cubic phase is 30 mol%. However, when the phase transition occurs, the concentration quenching takes place at a much higher doping concentration, i.e. the optimum content of Eu3+ in the structure is increased to about 80 mol%. Moreover, with elevating the Eu3+ content, the local coordination environment of Eu3+ in the NaYbF4 host lattice is changed from inversion (centrosymmetric) to non-inversion symmetry (non-centrosymmetric), which is further confirmed by the theoretical calculation results via Judd-Oflet theory. Furthermore, compared with cubic samples, the hexagonal NaYbF4:0.8Eu(3+) nanoparticles show improved thermal stability. Importantly, utilizing hexagonal NaYbF4:0.8Eu(3+) nanoparticles, a designed white light-emitting diode emits warm white light, with desired color coordinates (0.398,0.374), high color rendering index (86.3), and low correlated color temperature (3537 K). Besides, NaYbF4:xEu(3+) nanoparticles and their flexible polydimethylsiloxane films exhibit potential applications in high-temperature optical anti-counterfeiting. This work may support a new perspective for tailoring the concentration quenching and thermal stability of various phosphors. (C) 2022 Elsevier Ltd. All rights reserved.
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