Band-Gap Modulation in Single Bi3+-Doped Yttrium–Scandium–Niobium Vanadates for Color Tuning over the Whole Visible Spectrum

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• 作者：Fengwen Kang ; Haishan Zhang ; Lothar Wondraczek ; Xiaobao Yang ; Yi Zhang ; Dang Yuan Lei ; Mingying Peng
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：April 26, 2016
• 年：2016
• 卷：28
• 期：8
• 页码：2692-2703
• 全文大小：1204K
• 年卷期：0
• ISSN：1520-5002

文摘

The use of rare-earth (RE) (e.g., Eu²⁺/Ce³⁺) ions as single luminescent centers in phosphors with tailorable emission properties has been extensively studied for their potential use in white LEDs. However, significant limitations remain, in particular, for red-emitting phosphors due to the inherently broad excitation bands which result from the underlying d–f transitions and span large parts of the visible spectral region. Guided by density functional theory calculations on the ligand structure of the non-RE Bi³⁺ ion, we report here on an alternative class of phosphors, [(Y,Sc)(Nb,V)O₄:Bi³⁺], which exhibit homogeneous Bi³⁺ luminescence. In these materials, adjustment of the cation fractions enables dedicated tailoring of the excitation scheme within the spectral range of ∼340–420 nm and, in the meanwhile, allows for tunable emission spanning from about 450 nm (blue) to 647 nm (orange-red). The practical absence of any overlap between the emission and excitation spectra addresses the issues of emission color purity and visible reabsorption. Tailoring through band-gap modulation is achieved by single or parallel substitution of Nb by V and Y by Sc. Such topochemical design of the ligand configuration enables modulation of the electronic band gap and thus provides a new path toward tunable phosphors, exemplarily based on Bi³⁺ single doping.