Molecular design of inorganic scintillators: from alkoxides to scintillating materials

In this paper we report on preliminary results obtained on sol-gel derived inorganic scintillators. A new general scheme based on the use of alkoxide chemistry is proposed for the preparation of various scintillating materials including LuBO3, GdBO3, LuPO4 and Lu2SiO5. The materials are obtained as monophasic powders and as homogeneous transparent thin films for borates and silicate. Thermal behaviour is analysed and a study of the oxidation state of cerium ions is proposed by combining X-ray photoelectron spectroscopy and X-ray absorption near edge structure spectroscopy. A mixture of Ce3+ and Ce4+ is observed in proportions depending on the material. This presence of Ce4+ ions does not seem to greatly affect the observed scintillation yields of the materials. Efficient sol-gel derived scintillators have been prepared both as powders and thin films. The preparation of optical quality scintillator thin films could be the starting point for a new generation of scintillating materials. Finally, the versatility of the proposed synthesis route will allow extension of this study towards various other materials.