Morphology and visible photoluminescence modulation in dye-free mesoporous silica nanoparticles using a simple calcination step. (August 2022)

• Record Type: Journal Article
• Authors: Shamim, Shadmani; Hornyak, Gabriel L.; Crespy, Daniel; Kyaw, Htet; Bora, Tanujjal
• Is Part Of: Materials research bulletin. Volume 152(2022)
• Publication Date: 2022-08
• Subjects: Mesoporous silica nanoparticle -- Photoluminescence -- Calcination -- Dye-free -- Defects -- Carbon impurity; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2022.111842
• Languages: English
• ISSNs: 0025-5408

Abstract

Highlights: A dye-free fluorescent SiO2 porous nanoparticles is presented. TEM & BET analysis confirmed the mesoporous structure of the SiO2 nanoparticles. The porous dye-free SiO2 nanoparticles displayed strong visible light fluorescence. Fluorescence intensities are modulated with varying calcination temperatures. The visible light fluorescence is mainly attributed to carbon impurities. Abstract: Synthesis of dye-free mesoporous silica nanoparticles and the effect of calcination on their photoluminescence properties are reported here. Mesoporous silica nanoparticles were synthesized using a modified Stöber method and calcined at different temperatures. Samples were characterized by transmission electron microscopy (TEM), BET surface area analyzer, thermogravimetry analyzer, Fourier Transform Infrared spectroscopy (FTIR), photoluminescence spectroscopy, and X-ray photoelectron spectroscopy (XPS). Silica nanoparticles calcined at 400 °C exhibited maximum porosity with highest specific surface area of 828 m 2 .g –1 . Uncalcined porous nanoparticles exhibit broad visible light photoluminescence (from 400 nm to 600 nm), and its intensity varies significantly after calcination, mainly due to the creation of carbon impurities and oxygen defects within the silica lattice. Carbon impurities during calcination are formed from the remaining organic residue at the nanoparticle's surface and can be removed by calcining the particles above 400 °C and thereby, improving the visible light photoluminescence intensity of these nanoparticles. Graphical abstract: Image, graphical abstract