Luminescent coatings prepared from optimized YAG:Ce nanoparticles

Y3Al5O12 nanoparticles doped with Ce3 + ions (YAG:Ce) were prepared by solvothermal synthesis. For short reaction times, very small YAG:Ce grains are formed and aggregate together with a preferred orientation, as proved by X-ray diffraction analysis and transmission electron microscopy. For longer reaction times, individual well-crystallized and faceted YAG:Ce nanoparticles are observed. The growth of the nanoparticles under solvothermal conditions seems to be driven by self-oriented aggregation and coalescence leading to single-crystals at the nanoscale. For larger YAG:Ce nanoparticles (18 ± 5 nm), the internal luminescence quantum yield is measured to be 27 ± 5% and seems only limited by surface defects or species, regarding the high crystalline quality of the nanocrystals. Such nanocrystals are deposited onto glass substrates by spray-deposition, a simple deposition technique which allows the formation of binder-free films. Micron-thick translucent films, exclusively composed of stacked YAG:Ce nanoparticles, are formed, while the particle morphology and optical properties are not modified by the deposition process.