Daylight-White-Emitting and Abnormal Thermal Antiquenching Phosphors Based on a Layered Host SrIn2(P2O7)2

Single-phase white-emission phosphors possess a judicious usage potential in phosphor-converted white-light-emitting diodes (WLEDs). Recently, numerous efforts have been made toward the development of new patterns of white-emitting phosphors that achieve excellent quantum yield, superior thermal stability, and applaudable cost effectiveness of WLEDs. Finding suitable single-component white phosphor hosts to provide an ideal local environment for activators remains urgent. Inspired by the original discovery of the promising host MgIn₂(P₂O₇)₂ (MIP) and its structural dependence on alkali-metal cations, we synthesized a brand-new phosphor host, SrIn₂(P₂O₇)₂ (SIP), via the traditional solid-state reaction. Its crystal structure was determined using an ab initio analysis and the Rietveld method. It belongs to a monoclinic unit cell with the space group C2/c. Besides, SIP exhibits a special layered three-dimensional framework in which the monolayer [SrO₁₀]_∞ was surrounded by a bilayer [In₂P₄O₁₄]_∞ made of the InO₆ octahedra and P₂O₇ groups. A series of pure SIP:Tm³⁺,Dy³⁺ phosphors with tunable blue-white-yellow emission were prepared by adjusting the dopant concentration and utilizing the Tm³⁺-Dy³⁺ energy transfer. The daylight-white-emitting phosphor SIP:0.01Tm³⁺,0.04Dy³⁺ (the correlated color temperature is 4448 K) exhibits an abnormal thermal antiquenching property, and the emission intensity of 423 K reaches 103.7% of the initial value at 300 K. On the basis of the temperature-dependent lattice evolution and microenvironment analysis, the reduction of β and lattice distortion can lead to lower asymmetry of the activators and benefit the compensation of trapped-electron thermal activation. In this work, an integration study was carried out on the crystal structure of the new matrix, the occupation of the luminescent center, the interaction of different activators in the host, and the distortion degree of the local structure for the activators, which is of great practical sense for producing a novel single-matrix white phosphor possessing superior thermal endurance for UV-light-stimulated WLEDs.

Synthesis, structure and characterization of three new Mg-containing phosphates with deep-UV cut-off edges

Three new Mg-containing phosphates, AMg₂P₃O₁₀ (A = Li, Cs) and Rb₂MgP₂O₇, have been successfully synthesized using a high-temperature solution method.

Three new phosphates, Cs8Pb4(P2O7)4, CsLi7(P2O7)2 and LiCa(PO3)3: structural comparison, characterization and theoretical calculation

Three new phosphates with a short cutoff edge were obtained, and the structural comparisons were discussed in detail.

Modulation of perovskite-related frameworks induced by alkaline earth metals in phosphate fluorides A2MPO4F (A = K, Rb; M = Ba, Ca)

A₂CaPO₄F (A = K, Rb) are isomorphs. The 1D zig-zag [FA₄Ca₂]_∞ chains in the two compounds belong to the 1D perovskite-related structure.

Four alkali metal molybdates with two types of Mo–O chains, ABMo3O10 (A = Li, B = Rb; A = Li, Na, K, B = Cs): synthesis, structure comparison and optical properties

The effects of cation size on the framework structures of four stoichiometrically equivalent alkali metal molybdates were discussed in detail.