The effects of down- and up-conversion on dual-mode green luminescence from Yb super(3+)- and Tb super(3+)-doped LaPO sub(4) nanocrystals

Monoclinic LaPO sub(4) nanocrystals doped with Yb super(3+) and Tb super(3+) ions were synthesised by co-precipitation followed by annealing at 900 degree C. These materials exhibited intense luminescence under ultraviolet (UV) and near infrared (NIR) irradiation. The structural properties of the pr...

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Bibliographic Details
Published in:Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2013-08, Vol.1 (34), p.5410-5418
Main Authors: Grzyb, Tomasz, Gruszeczka, Aleksandra, Wiglusz, Rafal J, Lis, Stefan
Format: Article
Language:English
Subjects:
Computational efficiency
Computing time
Coprecipitation
Luminescence
Mathematical analysis
Nanocrystals
Ultraviolet
Upconversion
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Summary:Monoclinic LaPO sub(4) nanocrystals doped with Yb super(3+) and Tb super(3+) ions were synthesised by co-precipitation followed by annealing at 900 degree C. These materials exhibited intense luminescence under ultraviolet (UV) and near infrared (NIR) irradiation. The structural properties of the products were analysed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The obtained nanomaterials had a single phase, a spherical shape of nanocrystals and an average size of 42 plus or minus 5 nm. The spectroscopic properties of LaPO sub(4):Yb super(3+),Tb super(3+) nanocrystals were investigated in detail using excitation and emission spectra. Additionally, the luminescence lifetimes for both Tb super(3+) and Yb super(3+) ions were calculated from the measured decays. The optimal dopant concentrations were estimated with respect to the intensity of luminescence. A cooperative energy transfer (CET) mechanism, which causes the observed up-conversion, was proposed because of the observed dependence of integral intensity on the power of the pumping laser. The calculated efficiencies of the CET were much higher than the efficiencies of the opposing quenching processes; these parameters were measured in samples doped with high amounts of Tb super(3+) ions. These materials demonstrated intense green up-conversion in addition to UV-excited emission.
ISSN:2050-7526
2050-7534
DOI:10.1039/c3tc31100g