Subcategory: Materials Science
Kristopher Liggins - Alabama A&M University
Co-Author(s): Dr. Rami Bommareddi, Alabama A&M University, AL; Dr. Vernessa Edwards, Alabama A&M University, AL
Sodium borate glasses doped with rare-earth ions were prepared from a mixture of B2O3, Na2CO3, Dy2(SO4)3, Sm2(SO4)3, Tb2(CO3)3, and AgO. All the samples were melted at 1450°C for an hour and thirty minutes. The samples were made by the melt quenching technique. Sample A has a concentration of 1% silver and 1.5% respectively of Tb3+, Sm3+, and Dy3+. Sample B has a concentration of 3% silver and 1% respectively of Tb3+, Sm3+, and Dy3+. The role of silver (II) oxide within the glass compositions were studied by testing the sample’s emission and color coordinates at 375 nm and 405 nm laser excitation before and after heat treatments. The samples emission intensities were initially compared to determine if any differences between the 1% Ag and 3% Ag samples exist. During analysis it was found that the intensity of the 3% silver sample was more than that of the 1% sample, even though the concentration of rare-earths in the 1% sample was higher. The time and temperature of heat treatments varied from 4 hours, 6 hours, 3 hours, 5 hours, and 21 hours at 470˚C, 470˚C, 475˚C, 475˚C, and 472˚C respectively. In addition to the fluorescence outputs of the samples, microscopic images were taken to determine the distribution of silver within the glass samples before heat treatment. These images were compared to those taken after heat treatments. The samples were also tested for their lifetimes at 375 nm and 405 nm excitation to determine which rare-earth ion was responsible for the peaks seen in emission output.. Preliminary results show that after the initial heat treatment was preform on Sample A, an increase of 40% occurred in the sample’s fluorescence. We also found the color coordinates at 405 nm laser excitation for Sample A to be x= 0.543, y= 0.416 which differs from those of Sample B x= 0.486, y=0.405 before any heat treatments were performed. The microscopic images also revealed many changes that occurred during heat treatments. These changes include but are not limited to the migration of silver particles from one place to another, clusters of silver particle merging together, and the splitting of clustered silver particles within the glass matrix. These are just the initial findings as the research on these glasses still continue.ern Abstract 11.docx
Funder Acknowledgement(s): This study was supported, in part, by a grant from NSF grant HRD 546965.
Faculty Advisor: Dr. Rami Bommareddi, firstname.lastname@example.org
Role: During this research I have been involved in every aspect. From weight and mixing the chemicals, to pouring the melt into a mold to make a thin glass piece, polishing multiple glass samples, microscopically imaging glass samples for nano-particles, recording the emission and color coordinates of the samples, and also heat treating samples to alter the nano-structures.