[Luminescence properties of thenardite activated with Dy3+ under vacuum ultraviolet excitation].

Na2SO4: Dy3+ phosphors were prepared by heating pure natural thenardite (Na2SO4) with DyF3 at 900 degrees C for 25 min in air studied the Luminescence properties of Na2SO4: Dy3+ were studied by synchrotron radiation. Their photoluminescence (PL) spectra were also investigated under vacuum ultraviolet-ultraviolet (VUV-UV) at room temperature. According to the emission spectra, the yellow-blue ratio (Y/B) is different under different concentrations of Dy3+ and the position of excitation.

[Luminescence properties of thenardite activated with Cu].

Na2SO4:Cu phosphors were prepared by heating pure natural thenardite with Cu at 1100 degrees C for 20 min in air. Their photoluminescence spectra were investigated at room temperature. The shapes of emission spectra depend on the excitation wavelengths, The emission spectrum under 260 nm excitation consists of a broad band with a peak at 430 nm, which can be attributed to the 3d 94s --> 3d10 transition within Cu+.

[Luminescence properties of thenardite activated with Tm3+ under vacuum ultraviolet excitation].

The Na2 SO4 : Tm3+ phosphor was synthesized by the high temperature solid state reaction method in air. The crystalline structure was examined by X-ray diffraction (XRD). Narrow bands observed in emission spectra were well identified with the electronic transitions within the 4f12 configurations of Tm3+, and the excitation spectrum is consisted of strong bands assigned to the 4f12 --> 4f11 5d transition at 183 nm, the O(2-)-Tm3+ charge transfer band at 170 nm and weak bands assigned to host absorption (130, 223 and 258 nm).