Three-primary-color upconversion luminescence in rare earth-doped β-NaLuF_4 microtubes

摘要

Lanthanide ions-doped NaLuF_4 hexagonal-prismatic microtubes have been successfully synthesized via a facile hydrothermal approach for the first time. The as-grown microtubes are determined to be pure hexagonal (β-) NaLuF_4 phase with an outermost diameter of about 3 μm and a length of approximately 40 μm. The Yb~(3+)/Er~(3+)(Tm ~(3+))-codoped NaLuF_4 microtubes emit bright three-primary-color (red, green, and blue) light under 980 nm laser diode excitation undergoing an upconversion. Mechanisms for the excitation and emission were analyzed based on the emission spectra, the plot of luminescence intensity to pump power and a simplified energy level diagram.