Degradation of commercial Gd₂O₂S:Tb phosphor

Abstract

The degradation of Gd2O2S:Tb phosphor was studied with Auger Electron Spectroscopy (AES) and Cathodoluminescence (CL). The surface reactions were monitored with AES while the light output was measured with a PC2000‐UV spectrometer. The CL of the Gd2O2S:Tb was excited with a 2 keV energy electron beam with a beam current density of 26 mA/cm2. The CL and AES were measured simultaneously while the sample was bombarded with the electrons in an oxygen atmosphere. A comparison between the low energy peaks of the AES spectra before and after degradation showed significant differences in the shape of the different peaks. A linear least squares (LLS) method was applied to resolve the peaks. Elemental standards from Goodfellow were used in conjunction with the measured data to subtract the S and Gd peaks. A direct correlation between the surface reactions and the CL output was found. The CL decreased while the S was removed from the surface during electron bombardment. A new non‐luminescent surface layer that formed during electron bombardment was responsible for the degradation in light intensity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Photo/cathodoluminescence and stability of Gd2O2S:Tb,Pr green phosphor hexagons calcined from layered hydroxide sulfate

“…4,16 Gd 2 O 2 S:Pr phosphor powder finds application in X-ray microscope, soft X-ray phosphor screen for water window, and so forth. 17 On the other hand, Gd 2 O 2 S:Tb phosphor is widely used for display purposes in TV screens, CRT tubes, 18 and X-ray intensifying screens 19 due to its highly bright and efficient green emission under UV, cathode ray, and X-ray excitations. 20 Gd 2 O 2 S:Tb scintillator is useful in X-ray imaging and neutron radiography, 21,22 since it exhibits substantially better light output than the classic ZnS(Ag)/LiF material [21][22][23] by its much higher neutron capture cross-section and intrinsic conversion efficiency (~20%).…”

Fabrication of Gd2O2S: Pr, Ce, F Scintillation Ceramics by Pressureless Sintering in Nitrogen Atmosphere

“…Sulfur in Gd 2 O 2 S is easily removed because of its high volatility. Dolo et al reported that the cathodoluminescence (CL) decreased after electron bombardment on the surface and the degradation in light intensity was caused by a new nonluminescent surface layer that formed due to the desorption of sulfur from the surface. It is difficult to maintain the original phase at high sintering temperature for 6 h, and thus, the sintering conditions must be carefully studied.…”

XPS analysis and luminescence properties of thin films deposited by the pulsed laser deposition technique

“…The trend of the S peak is not clear due to the influence of the Gd peak on the S peak. A linear least squares (LLS) method was previously applied to resolve the peaks for a similar study on the Gd 2 O 2 S:Tb 3+ powder [9]. It was shown that most of the S was also removed from the surface.…”