Oxidation suppression of Cu in alkaline aluminophosphate glass and the effects for radiation-induced luminescence characteristics

Daiki Shiratori,Hirokazu Masai,Noriaki Kawaguchi,Takumi Kato,Takayuki Yanagida,Go Okada,Daisuke Nakauchi

doi:10.1038/s41598-020-78510-z

Abstract

A glass phosphor is an attractive material for applications in radiation detections because of its high workability and availability with a wide range of chemical compositions. Recently, X-ray-induced luminescence of glasses containing various luminescent activators are actively investigated worldwide. In applications as phosphor, tailoring valence state of activators, which can take multiple valence states in glass, is very important. In this research, we studied effects of glass melting atmosphere on the valence state of copper-activator ion in alkaline aluminophosphate glasses and the radiation-induced luminescence characteristics. Optical absorption and X-ray absorption near edge structure spectra of Cu-doped glasses showed that the glass fused in Ar atmosphere contains higher concentration of Cu+ than those prepared in air. In addition, the presence of Cu+ enhances the photoluminescence (PL) quantum yield and PL kinetic constant. Furthermore, the increase of Cu+ concentration resulted an improvement of the X-ray-induced scintillation and thermally-stimulated luminescence intensity.

Highlights

A glass phosphor is an attractive material for applications in radiation detections because of its high workability and availability with a wide range of chemical compositions
To enhance the functionalities as a fluorescent material, it is necessary to prepare the glass with a luminescent activator ion taking the desired valence state ( Cu+ in case of Cu-doped materials)
Thermal properties of all the specimens examined by differential thermal analysis (DTA) are shown in Table 1 and Figure S2

Summary

Introduction

A glass phosphor is an attractive material for applications in radiation detections because of its high workability and availability with a wide range of chemical compositions. We studied effects of glass melting atmosphere on the valence state of copper-activator ion in alkaline aluminophosphate glasses and the radiation-induced luminescence characteristics. Our group has investigated radiation-induced luminescence properties of various phosphate glasses doped with a range of luminescent activators[17,18,19,20] Among these researches, we have focused on Cu+ as a luminescence center element since Cu-doped phosphors generally show blue emission due to the 3 d94s1–3d10 transition of Cu+, of which the luminescence wavelength agreed well with the spectral sensitivity of common photodetectors. Based on results of X-ray absorption near edge structure (XANES) analyses of the valence of Cu ions in the glass, correlations between glass melting conditions and optical and X-ray-induced luminescence properties are discussed

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Conclusion