Yongzheng Wang

Growth, structural, thermal properties and spectroscopic characteristics of KTb(WO4)2 single crystal

Abstract KTb(WO4)2(KTW) single crystal with dimensions up to 30 mm×30 mm×10 mm was grown by the top-seeded solution growth (TSSG) method for the first time. The crystal structure was refined at room temperature by using single crystal X-ray diffraction data. Absorption and fluorescence spectra were measured at room temperature. The fluorescence lifetime of KTb(WO4)2 was 114 μs. The specific heat of the KTb(WO4)2 crystal was also measured at room temperature.

Syntheses and luminescent properties of new luminescence material Nd3PO7

Nd₃PO₇ was synthesized by solid state reaction techniques under high temperature in air atmosphere for the first time, the crystal phase of Nd₃PO₇ was investigated by X-ray powder diffraction and scanning electron microscopy, the results show that Nd₃PO₇ is monoclinic phase; the Nd: P: O = 3:1:7; Infrared spectroscopic study was used to obtain further structural information about the nature of bonding in Nd₃PO₇. Emission spectra of Nd₃PO₇ were investigated at room temperature using a fluorescence spectrometer in the visible portion of the spectrum. Excellent emission was observed at 441 nm when Nd₃PO₇ excited at 325 nm wavelength, which was assigned to the ⁴G_11/2-⁴I_9/2 transition of Nd³⁺ ions. All the investigated suggestions that Nd₃PO₇ is a good phosphor candidate applied in fluorescent materials.

Growth and characterization of high Nd-concentration single crystals LaxNd1-xPO4

In this paper, La_xNd_1-xPO₄(x=0, 0.5, 0.8) series crystals with high Nd-concentration were grown through a seed-inducing method using Li₂CO₃-2MoO₃ as a flux, and some factors influencing the quality of crystals were also discussed. The IR, absorption and fluorescence spectra of La_0.5Nd_0.5PO₄ crystals at room temperature were measured. High temperature X-ray diffraction was conducted to investigate the thermal expansion behavior of NdPO₄ crystals in the temperature range from 25°C to 900°C. Abnormal diffraction peaks shifts were observed along the (200) and (020) direction. The results indicate that as temperature increased, the crystal in the (200) and (020) direction contracted (from 25 °C to 700 °C) at first, and then expanded (from 700°C to 900°C). The mechanism responsible for the abnormal thermal expansion in NdPO₄ was attributed to the existence of rigid unit modes (RUM).