Wavelength and intensity multiplexing of metal nanoparticles for the fabrication of multicolored micro- and nanospheres

Multicolored micro- and nanospheres have been successfully fabricated by a novel method that was developed to broaden the selection of colors available in the application of metal nanoparticles (NPs). The colors of the metal NPs have been systematically tuned over a wide spectral range by wavelength and intensity multiplexing of three-colored NPs. Multicolor polystyrene micro- and nanospheres could be fabricated by combining the systematic color tuning of metal NPs and self-assembly of metal NPs on the surfaces of the polymer spheres. The agglomeration of metal NPs on the surfaces of polymer spheres could be prevented by optimizing the concentration of the metal NPs and the reaction pH.