Crystal structure and luminescence properties of a single‐component white‐light‐emitting phosphor Ca₈ZnLa(PO₄)₇:Eu²⁺,Mn²⁺

Abstract

A series of novel green emission Whitlockite-type Ca 8 ZnLa(PO 4 ) 7 :Eu 2+ and color tunable Ca 8 ZnLa(PO 4 ) 7 :Eu 2+ ,Mn 2+ phosphors were prepared by the solid-state reaction method in a reducing atmosphere. Its crystal structure and phase composition were identified by high-resolution transmission electron microscopy, selected area electronic diffraction, X-ray photoelectron spectroscopy, and X-ray powder diffraction Rietveld refinement, and it was found to be trigonal, belonging to R-3c (161) space group. The luminescence properties of Eu 2+ singly doped and Eu 2+ / Mn 2+ codoped Ca 8 ZnLa(PO 4 ) 7 phosphors were revealed in detail. Ca 8 ZnLa(PO 4 ) 7 : Eu 2+ is excitable over a broad range from 200 to 450 nm with a prominent green emitting. With varied Eu 2+ /Mn 2+ ratios, fine-tune emission under 365 nm excitation can be achieved from green (0.221, 0.468) to magenta (0.391, 0.276), especially the warm white light (0.392, 0.352), and CCT 3500 K can be obtained by the process of energy transfer between Eu 2+ and Mn 2+ . The ET mechanism in this system is managed via the dipole-dipole interaction with the maximum energy-transfer efficiency 82.8% based on the decay lifetime data. These results suggest that as-prepared phosphors can serve as promising candidates of UV-pumped w-LEDs. K E Y W O R D Soptical materials/properties, phosphates, photoluminescence, structure

A novel dazzling Eu3+‐doped whitlockite‐type phosphate red‐emitting phosphor for white light‐emitting diodes

“…So far, some Ca 3 (PO 4 ) 2 luminescence materials, such as Ca 8 MgLu(PO 4 ) 7 : Ce 3+ , Tb 3+ , Mn 2+ , (Ca,Sr) 10 Li(PO 4 ) 7 : Ce 3+ , Mn 2+ , and Ca 8 MgY(PO 4 ) 7 : Eu 2+ , Mn 2+ have been widely studied . Moreover, Ca 8 ZnLa(PO 4 ) 7 : Eu 2+ , Mn 2+ phosphor, whose luminescence properties and energy transfer have been reported by Liu and coworkers . However, the crystal structure and luminescent properties of Eu 3+ ‐doped Ca 8 ZnLa(PO 4 ) 7 have not yet been determined.…”

Continuously tunable broadband emission of Mn2+‐doped low‐melting point Sn–F–P–O glasses for warm white light‐emitting diodes

“…Currently, white light‐emitting diodes (w‐LEDs), as a novel type of luminescent devices, play crucial roles in applications such as indicators, backlights, automobile headlights, and daily lighting due to their small volume and excellent performances, such as energy savings, environmental friendliness, and durability . When w‐LEDs technology is applied to a high‐power development, the traditional packaging materials, such as silicone resin or resin, because of their poor thermal conductivity and stability, inevitably lead to severe yellowing and aging problems, resulting in reduced luminous efficiency and color shift in the w‐LEDs.…”

Syntheses, Crystal Structures and Luminescent Properties of Two New Heterometallic Phosphates: Sn2Ge(PO4)2(OH)2 and Sn2Mn(PO4)2

“…Metal phosphates have been paid much attention in the past few decades because of their diverse structures and the variety of applications such as ferroelectric, magnetism, ionic conductors, solid electrolyte batteries, and optical function, especially for luminescence . Currently, a number of the bimetallic phosphate phosphors have been synthesized by the conventional high‐temperature solid‐state method, such as SrZn 2 (PO 4 ) 2 :Tb 3+ , BaCdP 2 O 7 :Eu 2+ , Ca 9 Y(PO 4 ) 7 :Sm 3+ , CaZr(PO 4 ) 2 :Mn 2+ , Sm 3+ , Sr 8 CaSc(PO 4 ) 7 :Eu 2+ , Ce 3+ , Mn 2+ , Ca 9 Ce(PO 4 ) 7 :Mn 2+ , Tb 3+ , Ca 8 ZnLa(PO 4 ) 7 :Eu 2+ ,Mn 2+ , M II M’ IV (PO 4 ) 2 (M II =Cd, Ca, Sr, Pb, and Ba; M’ IV =Ge, Ti, Mo, Sn, Hf, Zr, Pu, Np, U, and Th), and they show high thermal stability and strong luminescence intensity. Although this method is more convenient to prepare compounds with high thermal stability, compared with other methods, which requires high reaction temperature, long reaction time and easily form glassy products .…”