Optical Properties and Stability of a Blue-Emitting Phosphor Sr2P2O7:Eu2+ Under UV and VUV Excitation

In this book chapter, divalent europium-activated alpha-distrontium diphosphate (α-S2P2O7) phosphors powders were successfully prepared by a conventional solid state reaction method under reduced atmosphere. Synthesized samples were characterized by means of X-ray diffraction (XRD) patterns, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy which signify the formation of pure single phase of Sr2P2O7. The optical properties were studied in both ultraviolet (UV) and vacuum ultraviolet (VUV) regions. The emission spectra were obtained by excitation excited at 131 or 320 nm present a single intense blue-emitting band from 350 nm to 500 nm due to the 5d-4f transition of Eu2+, indicating that α-Sr2P2O7:Eu2+ phosphor powders are suitable for near-UV light-emitting-diode (LED) chips (360-400 nm). The influence of temperature on the luminescence intensity of α-Sr2P2O7:1%Eu2+ was investigated. The activation energy (Ea) for thermal quenching was reported. The phosphor shows excellent thermal stability on temperature quenching. The luminescence properties show that this host material has a highly promising blueemitting phosphor for white-LED applications.

Keywords: Pyrophosphates, Eu2+, Photoluminescence, Phosphors, Light-emitting diodes.