Modulated single band red upconversion luminescence from Ho 3+ doped nanoparticles with two-wavelength excitation

摘要

AbstractSingle band red upconversion luminescence has the potential applications from science to engineering, however, suffered from low luminescence efficiency. Single band enhanced red upconversion luminescence from NaYF4: Ho nanoparticles has been realized with the modulation of two-wavelength excitation and the administration of cross relaxation between5F4,5S2→5F5and5I7→5I6of Ho3+. Compared to the sum intensities with single-wavelength excitation at 975?nm and 1150?nm, the upconversion intensity for red and green luminescence is enhanced by the factors of 13.04 and 0.46 respectively with two-wavelength excitation. The red/green ratio of upconversion luminescence intensity is modulated from 15.46 to 115.03 by controlling the interionic distance and cross relaxation between Ho3+ions. The microscopy mechanism of single band enhanced red upconversion luminescence with two-wavelength excitation at 1150?nm and 975?nm is ascribed to the ground state absorption of 1150?nm and excited state absorption of 975?nm, which was explored by power depended upconversion luminescence intensities, excitation spectra, and absorption spectrum. Besides, single band red upconversion luminescence from NaYF4: 10%Ho nanoparticles with the two-wavelength excitation shows the comparable intensity with that from NaYF4: 20%Yb, 2%Ho nanoparticles excited by 975?nm. Our results might provide a new method for the single band red upconversion luminescence with the applications in biology and three-dimensional displays.Highlights?Single band enhanced red UC luminescence is realized with two-wavelength excitation.?The R/G ratio is modulated from 15.46 to 115.03 with various doped concentration.?The microscopy mechanism is attributed to GSA of 1150?nm and ESA of 975?nm.?The intensity of NaYF4: 10%Ho NPs is comparable to that from NaYF4: 20%Yb, 2%Ho NPs.]]>