New Structural Design Strategy: Optical Center VO₄-Activated Broadband Yellow Phosphate Phosphors for High-Color-Rendering WLEDs

Abstract

Optical center VO4-activated non-rare-earth phosphors featuring impressive broadband emission are emerging as alternatives to rare-earth phosphors for lightings. However, most VO4-activated phosphors merely exist in vanadates and suffer from serious luminescence thermal quenching, which hinder the development of advanced VO4-activated phosphors. Herein, we put forward a new strategy of constructing optical center VO4 in non-vanadate compounds with thermal stability to enrich the number and variety of VO4-activated phosphors and improve their thermal stability. In this study, detailed structural analysis and theoretical calculation show that we have successfully constructed VO4 groups with a highly electron-localized property by substituting P5+ in the K2BaCa­(PO4)2 (KBCP) host with V5+, confirming the formation of VO4 centers. In K2BaCa­(PO4)2–x (VO4) x (KBCP2–x V x ) compounds, the appearance of VO4 groups significantly enhances the absorption efficiency of near-ultraviolet light, yielding a broadband yellow emission centered at 568 nm, with a full width at half-maximum of 213 nm. At 150 °C, the KBCP1.8V0.2 sample shows superior thermal stability with an emission loss of only 10%, surpassing the performances of VO4-activated vanadate phosphors ever reported. Using the KBCP1.8V0.2 phosphor, the resulting white-light-emitting diodes (WLEDs) show a high color rendering index of 87.3–93.4 and a wide range of correlated color temperatures of 4357–6510 K. Our results may stimulate more research on anionic-group-activated phosphors and accelerate the development of advanced VO4-activated phosphors.

Bi3+ Full Occupancy Efficient Ultra-Wideband Emission Based on Triangle Pore Structure

“…As x increases, the absorption band undergoes a blue shift, indicating that the conduction band of the crystal shrinks and the band gap increases. The band gap of the crystal can be obtained using the Kubelka–Munk formula and Tauc plot method: − F false( R ∞ false) = false( 1 − R ∞ false) 2 2 R ∞ R ∞ represents reflectivity. E g represents optical band gap, which is obtained through the linear region of [ F ( R ∞) h ν] 1/γ = B ( h ν – E g ) = 0, where h represents the Planck constant, ν represents the photon’s frequency, the γ factor is equal to 2, and B is a constant.…”

Synergistically Enhanced Electrochemical Sensing of Food Adulterant in Milk Sample at Erbium Vanadate/Graphitic Carbon Nitride Composite

“…The stretching vibrations of (N-H) in −NH 2 and =N−H can be defined from the broad peak at 3381.80 cm −1 . The confirmed s-triazine ring of the bending vibration is at 810.39 cm −1 [ 34 , 35 , 36 , 37 ]. The tetragonal crystal system with a 141/amd space group of ErVO 4 is shown in Figure 1 c. Er 3+ is attached to eight equivalent O 2− atoms, and V 5+ is bonded to four equivalent O 2− atoms.…”

Vinylene-Linked Emissive Covalent Organic Frameworks for White-Light-Emitting Diodes

“…Conversely, the latter exhibited cool white light characteristics. Notably, the WLED device incorporating VL-COF-1 achieved a CRI of 79.1, surpassing the CRI of a commercial WLED light source which utilized a yellow-emitting Y 3 Al 5 O 12 :Ce 3+ phosphor and a blue InGaN chip [ 47 , 48 ]. This indicates that the fabricated WLED device can offer superior light quality.…”