Key Words:Light emission;Europium - High temperature applications - Light emitting diodes - Phosphates - Phosphors - Photoluminescence - Quality control - Quenching - Solid state reactions - Strontium compounds - Thermodynamic stability;Blue emission - Concentration quenching - Dipole dipole interactions - High temperature solid-state reaction - Optimum concentration - Photoluminescence properties - Radiation reabsorption - Temperature dependent
Abstract:A series of blue-emitting Ba<inf>5 &minus; x</inf>Cl(PO<inf>4</inf>)<inf>3</inf>:xEu^{2 +}(0.004 &le; x &le; 0.016) phosphors were synthesized by conventional high-temperature solid state reaction. The structure and photoluminescence (PL) properties of the phosphors were investigated. The as-prepared phosphors exhibit broad excitation band ranging from 250 to 420 nm, and strong asymmetric blue emission band peaking at 436 nm. The optimum concentration of Eu^{2 +}in the Ba<inf>5</inf>Cl(PO<inf>4</inf>)<inf>3</inf>:Eu^{2 +}phosphor is x = 0.01, and the concentration quenching mechanism is verified to be the combined actions of dipole-dipole interaction and radiation re-absorption mechanism. The thermal stability of Ba<inf>5</inf>Cl(PO<inf>4</inf>)<inf>3</inf>:Eu^{2 +}was evaluated by temperature-dependent PL spectra. Compared with that of commercial BaMgAl<inf>10</inf>O<inf>17</inf>:Eu^{2 +}(BAM) phosphor, the Ba<inf>5 &minus; x</inf>Cl(PO<inf>4</inf>)<inf>3</inf>:xEu^{2 +}phosphors exhibit similarly excellent thermal quenching property. In addition, the CIE chromaticity coordinates of Ba<inf>5 &minus; x</inf>Cl(PO<inf>4</inf>)<inf>3</inf>:xEu^{2 +}(0.004 &le; x &le; 0.016) were calculated to evaluate the color quality. All the results indicate that Ba<inf>5</inf>Cl(PO<inf>4</inf>)<inf>3</inf>:Eu^{2 +}is a promising candidate phosphor for near-ultraviolet (n-UV) pumped LED. &copy; 2016 Elsevier B.V.
Volume:171
Translation or Not:no