Red phosphor often plays a crucial role in enhancing the lighting quality of WLEDs. However, it still remains difficult to develop a red phosphor with high efficiency, outstanding thermal stability,...

In the development of novel phosphors for solid-state light applications, the suitable excitation peak matching with blue LED chip was usually neglected. However, the excitation peak of phosphors was strongly related to the Stocks shift, crystal field splitting, and centroid shift. Here, an environmentally friendly borate phosphor KSr 4 B 3 O 9 : Eu 2+ with the maximum excitation peak position at ∼460 nm was prepared in a quite mild synthesis condition. With a blue light excitation, KSr 4 B 3 O 9 : Eu 2+ phosphors could emit a bright yellow light centered at ∼560 nm, which could be attributed to the drastic centroid shift and strong crystal field splitting. The strong electron cloud overlaps between Eu-O and the high electron density on the O atom turned out to be the main reason that induces the strong nephelauxetic effect. In addition, the strong crystal field splitting was benefited to the relatively short average Sr-O distance and the large Sr-O distances distribution range from ∼2.23 to 2.96 Å. Meanwhile, the Eu 2+ occupation of all the Sr 2+ sites in KSr 4 B 3 O 9 host identified by Rietveld refinement, cryogenic emission spectra, and Eu 3+ fluorescent probe gave another evidence to the wide absorption region. The final WLED device and three-dimensional colorful artwork were fabricated and displayed to suggest a potential application in the solid-state lighting field and some expressions of esthetic concepts.

In this work, a series of Eu3+ doped double perovskite phosphors Ba9La2W4O24: xEu3+ (0.2 ≤ x ≤ 1.0) were synthesized by high temperature solid-state method. The phase purity and morphology...

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MMCT-induced Bi3+-activated green-yellow phosphors suitable for full-spectrum LEDs.