Ultrasensitive Polarized Up-Conversion of Tm³⁺–Yb³⁺ Doped β-NaYF₄ Single Nanorod

Abstract

Up-conversion luminescence in rare earth ions (REs) doped nanoparticles has attracted considerable research attention for the promising applications in solid-state lasers, three-dimensional displays, solar cells, biological imaging, and so forth. However, there have been no reports on REs doped nanoparticles to investigate their polarized energy transfer up-conversion, especially for single particle. Herein, the polarized energy transfer up-conversion from REs doped fluoride nanorods is demonstrated in a single particle spectroscopy mode for the first time. Unique luminescent phenomena, for example, sharp energy level split and singlet-to-triplet transitions at room temperature, multiple discrete luminescence intensity periodic variation with polarization direction, are observed upon excitation with 980 nm linearly polarized laser. Furthermore, nanorods with the controllable aspect ratio and symmetry are fabricated for analysis of the mechanism of polarization anisotropy. The comparative experiments suggest that intraions transition properties and crystal local symmetry dominate the polarization anisotropy, which is also confirmed by density functional theory calculations. Taking advantage of the REs based up-conversion, potential application in polarized microscopic multi-information transportation is suggested for the polarization anisotropy from REs doped fluoride single nanorod or nanorod array.

Intense multiphoton upconversion of Yb3+–Tm3+ doped β-NaYF4 individual nanocrystals by saturation excitation

“…S1 †), which is frequently used elsewhere. 10,29,30 The individual nanocrystals were attached to a glass slide through spin coating of colloids and evaporation of the solvent. We collected the luminescence signals from different spots and dened that the luminescent spots are captured from a single particle, if most of the spots exhibit similar luminescence intensity.…”

Polarization modulated upconversion luminescence: single particle vs. few-particle aggregates

“…When the examined object (e.g., a cell) contains a few number of nanoparticle probes, this intensity-based bioimaging, however, will face large uncertainties for the luminescence intensity of each nanoparticle is usually anisotropic. 8 Furthermore, commercial laser diodes used in bioimaging, such as a 980 nm laser, emit linearly polarized light and the luminescence of UC nanoparticles is naturally polarized. Therefore, the observed intensity of UC luminescence from nanoparticles confined in a cell, for instance, will depend not only on the number density of the particles, but also on the direction of the excitation polarization as well as the orientation of most nanoparticles.…”

“…Since the polarization anisotropy of lanthanide ions is largely dependent on the symmetry ( point group) of the crystal structure and the crystal orientation, 8 we located another nanodisk with its c axis parallel to HP (Fig. 3D, S2C †), and measured its UC luminescence at the excitation polarization angles from 0°to 360° (Fig.…”

Simple method for simultaneously achieving red and green up-conversion luminescence

“…[1][2][3][4] The tunable range of the upconversion (UC) emission color, however, is seriously limited due to the nite excitation wavelength, type of activator, and inappropriate emission levels, which also hinder the wide application of UCL materials. 5,6 Current methods for achieving multicolor emission can be divided into three types. (1) The rst type of method involves achieving emissions from multiple samples by exciting them with a single wavelength.…”