Multi-site occupancies and luminescence properties of cyan-emitting Ca9-xNaGd2/3(PO4)7∶Eu2+ phosphors for white light-emitting diodes

• 作者: Shihua Liu Bin Deng Junhui Yang Jinhua Liu Jun Chen Fanhua Zeng Huanyou Wang Ruijin Yu Gongguo Zhang
• 来源期刊: 稀土学报（英文版）
• 年，卷（期）: 2022,（2）
• 所属期刊栏目: SPECTROSCOPY, LUMINESCENCE AND PHOSPHORS
• 页码范围: 243-252
• 页数: 10页
• 语种: 英文

摘要

Cyan-emitting Ca9NaGd2/3(PO4)7∶Eu2+ phosphors were synthesized via high temperature solid-state route.X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to verify the phase and morphology of the Ca9NaGd2/3(PO4)7∶Eu2+ (CNGP∶Eu2+) phosphors.The as-obtained phosphor exhibits a broad excitation band of 250-420 nm,which is near the ultraviolet region.An intense asymmetric cyan emission at 496 nm corresponds to the 5d-4f transition of Eu2+.The multiple-site luminescent properties of Eu2+ ions in CNGP benefit from versatile structure of β-Ca3(PO4)2 com-pounds.The effective energy transfer distance is 5.46 nm (through the spectral overlap calculation),validating that the resonant energy migration type is via dipole-dipole interaction mechanism.Compared to the initial one at room temperature,the luminescent intensity of CNGP∶Eu2+ phosphor can maintain 77％ as it is heated up to 420 K.A white light-emitting diode (WLED) with excellent luminescent properties was successfully fabricated.Moreover,the CIE chromaticity coordinates of fabricated WLED driven by changing current just change slightly.