The role of Li+ in the upconversion emission enhancement of (YYbEr)(2)O-3 nanoparticles
authors Debasu, ML; Riedl, JC; Rocha, J; Carlos, LD
nationality International
journal NANOSCALE
keywords CODOPED Y2O3 NANOCRYSTALS; LIGHT-EMITTING-DIODES; SOL-GEL METHOD; UPCONVERTING NANOPARTICLES; LUMINESCENCE ENHANCEMENT; QUANTUM YIELD; WHITE-LIGHT; PHOTOLUMINESCENCE INTENSITY; NAYF4 NANOCRYSTALS; POWER DEPENDENCE
abstract The mechanism of upconversion enhancement for Li+-doped materials is still contentious. Attempting to settle the debate, here the upconversion emission enhancement of (Y0.97-xYb0.02Er0.01Lix)(2)O-3, x = 0.000-0.123, nanoparticles is studied. Li+ incorporation in the Y2O3 host lattice is achieved via co-precipitation and solid-state reaction routes. In contrast to numerous reports, elemental analysis reveals that the former method does not afford Li+-bearing nanoparticles. The solid-state reaction route accomplishes an effective Li+ doping, as witnessed by inductively coupled plasma atomic emission spectroscopy and X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy and powder X-ray diffraction showed an increase in nanoparticle size with increasing Li+ concentration. Rietveld refinement of powder X-ray diffraction data shows that the cubic lattice parameter decreases with increasing Li+ content. The emission quantum yield increases tenfold with increasing Li+ content up to x = 0.123, reaching a maximal value of 0.04% at x = 0.031. XPS and infrared spectroscopy show that the carbonate groups increase with increasing Li+ content, thus not supporting the prevailing view that the upconversion luminescence enhancement observed upon Li+ nanoparticle's doping is due to the decrease of the number of quenching carbonate groups present. Rather, the particle size increment and the decrease in the lattice parameter of the host crystals are shown to be the prime sources of quantum yield enhancement.
publisher ROYAL SOC CHEMISTRY
issn 2040-3364
year published 2018
volume 10
issue 33
beginning page 15799
ending page 15808
digital object identifier (doi) 10.1039/c8nr03608j
web of science category Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied
subject category Chemistry; Science & Technology - Other Topics; Materials Science; Physics
unique article identifier WOS:000443623800043
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journal impact factor 7.233
5 year journal impact factor 7.713
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