Color tunable Ba0.79Al10.9O17.14:xEu phosphor prepared in air via valence state control

Ziyao Wang,Yangai Liu,Jian Chen,Lefu Mei,Zhaohui Huang,Minghao Fang

doi:10.1007/s40145-017-0220-x

Ziyao Wang, Yangai Liu + Show 4 more

Open Access

https://doi.org/10.1007/s40145-017-0220-x

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Abstract

A series of luminescent Ba0.79Al10.9O17.14:xEu (x = 0.005–0.12) phosphors were prepared by high-temperature solid-state reaction in air atmosphere. The coexistence of Eu2+ and Eu3+ was observed and verified by photoluminescence (PL) and photoluminescence excitation (PLE) spectra, X-ray photoelectron spectra (XPS), and diffuse reflection spectra. The band emission peaking at 430 nm was assigned to 4F65D–4F7 transition of Eu2+, and another four emissions peaking at 589, 619, 655, and 704 nm were attributed to 4F–4F transitions of 5D0–7FJ (J = 1, 2, 3, 4) of Eu3+. The related mechanism of self-reduction was discussed in detail. The color of the Ba0.79Al10.9O17.14:xEu phosphors could be shifted from blue (0.23, 0.10) to red (0.42, 0.27) by doping Li+ ions, and the temperature dependence properties were investigated.

Highlights

White light emitting diode (WLED) is considered as a new generation of solid-state lighting source due to the characteristics of high energy efficiency, long lifetime, low energy consumption, etc
There are three traditional approaches to generate WLED: (1) YAG phosphor excited by blue LED, (2) direct white phosphor excited by ultraviolet (UV) LED, and (3) tricolor phosphor excited by near ultraviolet (NUV) LED
The self-reduction mechanism was discussed in detail based on the charge compensation model, and the reduction process could be controlled by tuning synthesis temperature and doping concentration of Eu3+ and Li+ ions to obtain the colorful tunable phosphor

Summary

Introduction

White light emitting diode (WLED) is considered as a new generation of solid-state lighting source due to the characteristics of high energy efficiency, long lifetime, low energy consumption, etc. Deshmukh et al [11] reported the effect of Ca2+ and Sr2+ ions on luminescence properties of BaAl12O19:Eu2+ phosphor. With the wide use of Eu2O3 as raw material in the synthesis of Eu-doped phosphors, the most common method to obtain Eu2+ is preparing under reducing atmosphere, such as H2, H2/N2, or C. In 1998, Zeng et al [16] reported the reduction of Eu3+ in SrB6O10 prepared in air and the luminescence of SrB6O10:Eu3+. A series of tunable Ba0.79Al10.9O17.14:Eu phosphors were prepared in air by high-temperature solid-state reaction. The self-reduction mechanism was discussed in detail based on the charge compensation model, and the reduction process could be controlled by tuning synthesis temperature and doping concentration of Eu3+ and Li+ ions to obtain the colorful tunable phosphor

Experimental

Results and discussion

Conclusions