Synthesis, characterization and application of luminescent silica nanomaterials†
Luminescent inorganic nanoparticles are interesting owing to their high stability and photophysical characteristics. In this study, luminescent ZnO–SiO2 nanoparticles (ZnOSiO2-X NPs, X = 1, 2, 3, 4) were designed and synthesized using the reverse microemulsion method. Here ZnO quantum dots are encapsulated and homogeneously distributed inside the silica matrix of ZnOSiO2-X NPs. The structural and optical properties of the nanoparticles were fully established using a variety of techniques. High-resolution TEM micrographs and electron diffraction data confirmed the presence of ZnO quantum dots inside silica nanoparticles. The ZnOSiO2-X NPs gave intense blue-white luminescence and the intensity varied with changes in the composition of the particles. In addition to fluorescence emission, these particles showed phosphorescence emission in solution and in the solid state. As a proof of concept, UV active invisible printing was demonstrated by using a ZnOSiO2/PDMS mixture in inkjet printing and mechanical stamping. The prepared stable luminescent NPs can be used for applications such as bioimaging, ink-jet printing or stamping in nanoelectronics.