On the unusual amber coloration of nanoporous sol-gel processed Al-doped silica glass: An experimental study

• Published in: Scientific reports Vol. 9; no. 1; pp. 12474 - 8
• Main Authors: Chang, Alvin, He, Yujuan, Arango, Maria A Torres, Wang, Maoyu, Ren, Yang, Feng, Zhenxing, Chang, Chih-Hung, Sierros, Konstantinos A
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 28.08.2019; Nature Publishing Group UK
• Subjects: Aluminum; Coloration; Optics; Science & Technology - Other Topics; Silica
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-48917-4

Silica is the most abundant component on the earth's surface. It plays an important role in many natural processes. Silica is also a critical material for a wide range of technical applications such as in optics and electronics. In this work, we discuss our recent experimental observation of the unusual amber coloration of aluminum doped sol-gel glass that has not been reported in the past. We characterized Al-doped sol-gel glasses, prepared at different sintering temperature, using a plethora of techniques to investigate the origin of this unusual coloration and to understand their structural and chemical properties. We used these experimental results to test a number of possible coloring mechanisms. The results suggested this coloring is likely caused by temperature-dependent aluminum-associated defect centers associated with different amorphous-to-crystalline ratios of the annealed sol-gel silica glass structures.