https://phys.org/news/2018-05-silicon-nanoparticles-bioimaging-drug-delivery.html > Scientists synthesized and studied three types of nanoparticles. Non-resonant yttrium vanadate particles (YVO4) were used as a control sample. Such particles do not affect the intensity of dye molecules. Gold and silicon particles of the same size coated with dye molecules placed at different distances from the surface were compared with the control sample. > Modelling and experiments have shown that attachment of dye to silicon particles may enhance the photoluminescence of the dye up to three times compared to gold particles. "Such enhancement is due to Mie resonances in silicon particles. It is important to note that the resonant wavelengths depend on particles' size. Because of the high refractive index, the Mie resonance of spherical silicon particles of about a hundred nanometers in size extends into the visible part of the spectrum. Thus, resonant silicon particles allow us to accelerate spontaneous emission and amplify the dye signal on the surface," says Sergei Makarov, head of ITMO's Laboratory of Hybrid Nanophotonics and Optoelectronics.