Structure of low-Ba3P4O13

Preparation and wide band emission characteristics of Eu2+/Eu3+ co-doped Ba3P4O13 phosphors

A series of phosphors Ba₃P₄O₁₃:xEu^2+/3+ (x = 0–0.1) were synthesized in a CO reduction atmosphere at a relatively low temperature (1113 K) by the solid-phase method. Crystallization and optical properties were investigated by using powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fluorescence spectrophotometry (PL/PLE), respectively. Under the excitation of 394 nm, the emission spectrum of the phosphor presents a broad spectrum band of Eu²⁺ and characteristic peaks of Eu³⁺ in the range of 400–750 nm, indicating the coexistence of Eu²⁺ and Eu³⁺ in the system. The occupation of Eu²⁺ and Eu³⁺ in the Ba₃P₄O₁₃ matrix position was discussed by Gaussian fitting and PL spectra. The existence of energy transfer between Eu²⁺ → Eu³⁺ in the system can be found through PL spectra under excitation of 251 nm. The emission color of the phosphor can be adjusted by changing the Eu ion doping concentration, resulting in the CIE color coordinates changing from (0.213, 0.215) blue to (0.249, 0.261) light bluish white. The results show that Ba₃P₄O₁₃:Eu^2+/3+ phosphors can be used as a potential single-doped single-host white light-emitting material.

Tunable color from blue to light bluish white region in Ba₃P₄O₁₃:Eu²⁺, Eu³⁺ phosphor is realized by controlling the Eu²⁺/Eu³⁺ ratio.

A simple route to full structural analysis of biophosphates and their application to materials discovery

An integrated suite of synthesis and characterisation techniques that includes synchrotron-based single crystal, powder X-ray diffraction, nuclear magnetic resonance and electron diffraction have been employed to uncover two new distinct structures in the Ca(x)Ba(2-x)P(2)O(7) polymorphic phosphate system. These materials have particular relevance for their application as both biomaterials and phosphors. Calcium barium pyrophosphate, CaBaP(2)O(7), was shown by a combination of spectroscopic and diffraction techniques to have two polymorphs distinct in structure from all of the five previously reported polymorphs of Ca, Sr and Ba pyrophosphate. A high temperature polymorph HT-CaBaP(2)O(7) prepared at 1200 °C is orthorhombic, of space group P(212121) with a = 13.0494 Å, b = 8.9677 Å, c = 5.5444 Å. A low temperature polymorph LT-CaBaP(2)O(7), prepared below 1000 °C, is monoclinic with space group P2(1)/c and dimensions a = 12.065 Å, b = 10.582 Å, c = 9.515 Å, β = 94.609°.