Unique adjustable UC luminescence pattern and directional radiation of peculiar-shaped NaYF4: Yb3+/Er3+ microcrystal particle

Abstract

A new design of peculiar-shaped β-NaYF4: 20% Yb3+/2% Er3+ hexagonal microcrystal (PSβHM) is proposed and its upconversion (UC) luminescence with adjustable color pattern is studied with near infrared excitation. Flower-like green UC luminescence emission pattern from blooming to withering process and intensive directional red emission are achieved by simply adjusting the focal point position of the excitation light. The mechanism that determines the unique UC luminescence phenomena are investigated systematically. The function of the internal light reflection and waveguide effect with annular microcavity is explored based on the structure characteristic of the hexagonal microplate. The current work may have great significant and potential applications in the development of optoelectronic device, color display, directional light and laser emission of microsystem.

Enhanced upconversion fluorescent probe of single NaYF4:Yb3+/Er3+/Zn2+ nanoparticles for copper ion detection

“…In order to obtain UCNPs with high luminescence efficiency and high surface to volume ratio so that a suitable single nanoparticle fluorescent probe can be designed, 30–32 the hexagonal NaYF 4 :Yb 3+ /Er 3+ microdisks and NaYF 4 :Yb 3+ /Er 3+ /Zn 2+ nanoparticles were synthesized by hydrothermal method. 33 As shown by scanning electron microscope (SEM) images ( Fig. 1(a and b) ) and size distribution graphs (Fig.…”