Uniform Nanostructured Arrays of Sodium Rare-Earth Fluorides for Highly Efficient Multicolor Upconversion Luminescence

摘要

Upconversion (UC) phosphors emit high-energy photons when they are excited by low-energy photons. This property is attractive for flat-panel displays, optical storage, bio-labels, solid-state lasers, and light-emitting diodes. High UC luminescence efficiency is typically generated by bulk materials and colloidal nanocrystals of hexagonal-phase lanthanide-doped rare-earth fluorides, but nanoarrays of single crystals are more desirable for solid-state lasers. The UC luminescence efficiency can be enhanced if the nanoarrays are aligned with photonic-crystal microstructures, and the faceted end planes of well-shaped crystals serve as good laser-cavity mirrors.