Abstract
Monodisperse silica of sizes from 0.67 µm to 3.2 µm was synthesized by a low-cost semi-batch technique free from the use of any stabilizer, porogen or surfactant. The effect of precursor (tetraethyl orthosilicate), hydrolyzing agent and catalyst concentration variation on the size, morphology, size distribution and optical properties of silica particles was studied. TEM observation and N2 adsorption-desorption studies showed the existence of a thin porous shell layer covering the outer surface of these particles. Absorption in the UV-Vis range confirmed that E’ and oxygen-deficiency centers (ODCs) prevailed. The observed broad photoluminescence including the UV, blue, green and red regions of the spectrum were attributed to the presence of ODCs, self-trapped excitons, hydrogen-related defects and non-bridging-oxygen hole centers respectively. A two-photon guided relaxation of free exciton was found to be a prominent cause of observed luminescence.
| Original language | English |
|---|---|
| Article number | 105632 |
| Pages (from-to) | 252-265 |
| Number of pages | 14 |
| Journal | Journal of Sol-Gel Science and Technology |
| Volume | 113 |
| Issue number | 1 |
| DOIs | |
| State | Published - 1 Jan 2025 |
| Externally published | Yes |
Keywords
- Luminescence
- Monodisperse
- Nucleation
- Semi-batch
- Stöber method
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- General Chemistry
- Biomaterials
- Condensed Matter Physics
- Materials Chemistry