ABSTRACT
Luminescent, lanthanide-doped (Ln3+) nanocrystals have unique optical properties that make them appealing for application in biomedical imaging. These nanocrystals absorb low-energy infrared photons and luminesce in the ultraviolet and visible regions due to the process of photon upconversion. The choice of dopant ratios and the host lattice influences the spectral properties and upconversion efficiencies of these particles. Thus, it is possible to design these upconverting nanoparticles (UCNPs) based on their intended application. This chapter will begin with a discussion of the theory and the synthetic approach to designing UCNPs with considerations regarding the core/shell structure and the intended emission spectra. The next section presents details about the fabrication of these nanoparticles including the synthesis of core material and different shelling materials. Patterning and manipulation of the surface chemistry of these particles are then discussed with regard to different classes of ligands that are used as coatings. Finally, characterization of these nanoparticles and determination of surface chemistry is presented.
