Spectral evidence for multi-pathway contribution to the upconversion pathway in NaYF4:Yb3+, Er3+ phosphors

Authors
Cho, YounghoSong, Si WonLim, Soo YeongKim, Jae HunPark, Chan RyangKim, Hyung Min
Issue Date
2017-03-14
Publisher
ROYAL SOC CHEMISTRY
Citation
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, v.19, no.10, pp.7326 - 7332
Abstract
Although upconversion phosphors have been widely used in nanomedicine, laser engineering, bioimaging, and solar cell technology, the upconversion luminescence mechanism of the phosphors has been fiercely debated. A comprehensive understanding of upconversion photophysics has been significantly impeded because the number of photons incorporated in the process in different competitive pathways could not be resolved. Few convincing results to estimate the contribution of each of the two-, three-, and four-photon channels of near-infrared (NIR) energy have been reported in yielding upconverted visible luminescence. In this study, we present the energy upconversion process occurring in NaYF4: Yb3+, Er3+ phosphors as a function of excitation frequency and power density. We investigated the upconversion mechanism of lanthanide phosphors by comparing UV/VIS one-photon excitation spectra and NIR multi-photon spectra. A detailed analysis of minor transitions in one-photon spectra and luminescence decay enables us to assign electronic origins of individual bands in multi-photon upconversion luminescence and provides characteristic transitions representing the corresponding upconversion channel. Furthermore, we estimated the quantitative contribution of multiple channels with respect to irradiation power and excitation energy.
Keywords
RARE-EARTH IONS; MULTIPHONON RELAXATION; UPCONVERTING NANOPARTICLES; ENERGY-LEVELS; LUMINESCENCE; CORE; NANOCRYSTALS; TEMPERATURE; INTENSITIES; MECHANISM; RARE-EARTH IONS; MULTIPHONON RELAXATION; UPCONVERTING NANOPARTICLES; ENERGY-LEVELS; LUMINESCENCE; CORE; NANOCRYSTALS; TEMPERATURE; INTENSITIES; MECHANISM; upconversion; phosphors; photophysics
ISSN
1463-9076
URI
https://pubs.kist.re.kr/handle/201004/122948
DOI
10.1039/c7cp00048k
Appears in Collections:
KIST Article > 2017
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML

qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE