Paper Title
Influence of Inorganic Salts on the Morphology and Luminescence Properties of YF3:Yb3+/Er3+ Upconverion Nanocrystals

Abstract
Recently, up-conversion nanoparticles (UCNPs), which convert higher wavelength excitations into lower wavelength emissions, have garnered a great deal of scientific attention owing to their distinctive optical properties, including large anti-Stokes shifts, sharp emission bands and long excited-state lifetimes [1]. Tuning the shape, size and luminescence properties of up-conversion nanophosphors is crucial for advanced research as well as to exploit new frontiers and applications in diverse fields. In the present study, we showed that the use of specific inorganic salt at precisely defined precursor composition dictate the simultaneous control over shape, size and optical emission properties of YF3:Yb3+/Er3+ nanocrystals (Table 1). YF3:Yb3+/Er3+ nanocrystals with novel morphologies including nanoplates, rice-grain like nanorods, and nanorods were successfully synthesized in the mixed solvent compositions (oleylamine (OM) and 1-octadecene (ODE)) at 310 C (Fig. 1 (a-f)). The UC luminescence properties reveal a strong red and comparatively weak green emission for all morphologies, while the intensity of rice-grain like nanorods is the highest (Fig. 1 (g)).