Ghamari M, Ghasemifard M. A Substantial Red and Blue Shift in the Band Gap of Gamma Alumina Through Controlling the OH/Al and Concentration of Sulfate Precursor. IJMSE 2020; 17 (2) :27-33
URL:
http://ijmse.iust.ac.ir/article-1-1478-en.html
Abstract: (11244 Views)
In this research, the dependence of the optical band gap of nano gamma alumina on the OH/Al ratio and concentration of aluminum sulfate is measured through diffuse reflectance spectroscopy (DRS) in the range of 900-1100nm. The samples were prepared via sol-gel method. The results showed that the band gap is pH and concentration-dependent but in a different way. The direct band gap of alumina was determined to be 3.40, 4.37, 3.90, and 3.65 eV for samples prepared at pH 6, 7, 8, and 9, respectively. A decreasing trend was observed with increasing pH (except for pH6). The lowering of the band gap may be associated with the variations in particles size during synthesis due to the quantum size effect. The values of the band gap increased significantly through increasing concentration from 3.90 to 5.65 eV for 0.1M to 0.3M. The role of concentration in band gap control is remarkably more than pH.
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Significant changes in band gap of gamma alumina by sulfate precursor concentration control
Finding the optical band gap by using diffuse reflectance spectroscopy and mathematical calculations
The highest and lowest band gaps obtained as 3.4 eV and 5.65 eV for 1A6 and 3A8
Type of Study:
Research Paper |
Subject:
Ceramics