Combustion synthesis of β-Ca 1.95P 2O 7:0.05Eu 2+ blue phosphor for near ultraviolet excitation

Abstract

Synthesis of a near ultraviolet light emitting phosphor β-Ca 1.95P 2O 7:0.05Eu 2+ for white LEDs by combustion method is reported. The photoluminescence, powder analysis and particle morphology of the phosphors were investigated using a luminescence spectrometer (LS), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). It was found that when the initiating combustion temperature reached 1000 °C, the phase of γ-Ca(PO 3) 2 which begun to appear at 700 °C, transformed into the target material – the phase of β-Ca 2P 2O 7. And the phase transition leads to a red shift of the emission peak about 9 nm. TEM images also confirm those results. The emission spectrum shows a single intense band centered at 421 nm while the excitation spectrum is a broad band extending from 250 nm to 410 nm, with two bands centered at 330 nm and 387 nm. The band at 387 nm is a main excitation peak matching the emission of near ultraviolet light (370–410 nm). The investigated phosphor is suitable for a NUV LED excitation.