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Title: Optical properties of transparent glass–ceramics containing lithium–mica nanocrystals: Crystallization effect

Graphical abstract: Optical properties of transparent Li{sub 2}O–MgO–Al{sub 2}O{sub 3}–SiO{sub 2}–F glasses containing lithium–mica nanocrystals are studied and crystallization condition has been evaluated and optimized to produce transparent glass–ceramics. Crystallization temperatures were determined by differential thermal analysis and crystalline phases were identified and quantified by X-ray diffraction. Scanning electron microscopy was used for morphological variations and UV–vis absorption spectroscopy for comparative analysis of transparency. In order to investigate the optical properties of transparent glass–ceramics, optical band gap, Fermi energy level and Urbach energy are calculated. The results of the investigation illustrate that band gap is reduced with increases in crystallization time and temperature. Enhanced orderliness in the arrangement of atoms might be regarded as possible reasons for the above changes. - Highlights: • The optimum temperature and time of crystallization were determined. • Li–mica nanocrystals with size of <30 nm were formed using a two-step heat-treatment. • Optical band gap and Fermi energy of nanocrystalline materials decreased with increasing of crystallization temperature and time. • Urbach band tailing was decreased with increasing of crystallization condition. - Abstract: Optical properties of transparent Li{sub 2}O–MgO–Al{sub 2}O{sub 3}–SiO{sub 2}–F glasses containing lithium–mica nanocrystals were studied. The crystallization condition of these glasses was evaluatedmore » and optimized to produce transparent glass–ceramics. Crystallization temperatures were determined by differential thermal analysis and crystalline phases were identified and quantified by X-ray diffraction. Scanning electron microscopy was used to detect morphological changes and UV–vis absorption spectroscopy was used for comparative analysis of transparency. In order to investigate the optical properties of the transparent glass–ceramics, optical band gap, Fermi energy level and Urbach energy were calculated. The results of the investigation illustrate that the band gap is reduced with increases in crystallization time and temperature. Enhanced orderliness in the arrangement of atoms might be regarded as possible reasons for the above changes.« less
Authors:
 [1] ;  [1] ;  [2]
  1. Department of Materials Science and Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)
  2. Materials and Energy Research Center (MERC), P.O. Box 31779-83634, Karaj (Iran, Islamic Republic of)
Publication Date:
OSTI Identifier:
22341800
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 48; Journal Issue: 9; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; ABSORPTION SPECTROSCOPY; CERAMICS; CRYSTALLIZATION; CRYSTALS; DIFFERENTIAL THERMAL ANALYSIS; ENERGY LEVELS; GLASS; HEAT TREATMENTS; LITHIUM; LITHIUM OXIDES; MAGNESIUM OXIDES; MICA; NANOSTRUCTURES; SCANNING ELECTRON MICROSCOPY; SILICA; SILICON OXIDES; X-RAY DIFFRACTION