Defect originated photoluminescence tuning of silica nanoparticles prepared by electron beam irradiation and their applications

Abstract

Considering the imminent importance of Silica (SiO2) nanoparticles (NPs), a highly rapid and one-pot scalable approach is being reported for their preparation. Electron-beam was used to derive the formation of SiO2 NPs, while in situ functionalization was carried out by α-Cyclodextrin (α-CD). XRD pattern of as prepared α-CD functionalized SiO2 NPs (i.e., α-CD@SiO2 NPs) revealed their amorphous nature, while imaging studies showed self-assembling of NPs into a porous structure. UV–visible absorption spectra showed multiple peaks at 233, 323, 390 and 455 nm, which signifies the presence of different kind of defects in the as prepared NPs. An interesting aspect of this work is tuning of the photoluminescent properties of NPs from blue to green by simply varying the absorbed dose. This could be attributed to the formation of a particular kind of ‘defects’ at a proportionate absorbed dose. These ‘defects’ act as emission centers (ECs) and were analysed through steady state and time-resolved emission studies. Notably, α-CD played significant role in influencing the composition of the NPs, whilst enhancing their colloidal stability and quantum yield. The prospective applications of α-CD@SiO2 NPs were explored in latent fingerprinting and thermosensing.