DOE OSTI2013
Silica and doped silica materials that are produced by a solution gelation (sol gel) process create versatile materials that have a large range of applications. Coatings, thin films and fibers, nanomaterials, energy conservation materials and optical materials can be synthesized with this technique. Specifically, silica gels have many advantages for optical materials. The gels are transparent and possess a high homogeneity and density. In addition, silica materials can be doped with different compounds to enhance scintillating properties. Gadolinium Oxyorthosilicate (GSO) is a promising candidate as a host for rare earth ions for scintillating applications because of its high stability, density and fast decay time. When a sol gel is dried conventionally, it often shrinks or cracks, forming a xerogel. This work will first focus on forming a transparent GSO host xerogel with sol gel chemistry. Once a transparent GSO xerogel is formulated and characterized, Ce 3+ will be doped into the GSO network. Non-radiative energy transfer from the Gd matrix ions to the Ce 3+ ions occurs because the GSO crystals activated are close in energy to the Ce 3+ f → d transition. GSO: Ce 3+ crystals are currently produced by growing single crystals via Bridgeman and Czochralski methods, which are expensive. Optical ceramics offers a cheap alternative method for making scintillating materials. Structural and thermal characterization of the xerogel will be investigated using X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The materials’ optical properties will be examined by UV-Vis absorption spectroscopy. XRD will be utilized to determine the crystal structure. This will tell determine if the gel is amorphous or crystalline. FTIR was be used to identify functional groups in the gel. DSC and TGA will be used to thermally characterize the gel’s crystallization temperature.