Comparison of Atomic and Electronic Structures of Silica and Sodium Silicate Glasses
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Glass scintillators may hold great promise for low-cost, large-volume, shapeable radiation detectors. However, the light yield and energy resolution of glass scintillators to-date have been more than an order of magnitude worse than for crystalline scintillators and far from the theoretical limits. Glass scintillators are fabricated by dissolving rare-earth dopants into a glass matrix. Their operation relies on gamma ray absorption in the glass generating electrons and holes that must migrate to a rare-earth activator atom to emit light. The transport of carriers in the glass limits the performance, particularly in glasses where the solubility limit of activator is low, since carriers may recombine non-radiatively before reaching an activator atom. In this work, we aim to use atomistic simulations to discover the nature of electron transport in specific glass materials and how it may be enhanced by tuning the composition or forming process. The analysis proceeds in two steps: generation of a computational model of a given glass’s atomic structure, then extraction of the electronic structure to correlate electronic structure with carrier transport. Here we report results for two glasses: silica (SiO2) and sodium silicate (Na2O:SiO2). Multiple compositions of the latter are studied, namely Na2O:SiO2 ratios of of 1:2, 1:3, and 3:7, with most results focused on the 3:7 composition. The overall goal is to establish a computational framework that can mimic a range of experimental glass structures by tuning computational parameters in the construction of the glass model, and enable studies of the correlation between atomic structure and electronic transport properties of the glass materials. These correlations would direct synthesis parameters for a given glass to optimize its transport properties.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1178383
- Report Number(s):
- LLNL-TR-663696
- Country of Publication:
- United States
- Language:
- English
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