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Morphology- and size-dependent spectroscopic properties of Eu(3+)-doped Gd2O3 colloidal nanocrystals.

Wawrzynczyk D, Nyk M, Bednarkiewicz A, Strek W, Samoc M - J Nanopart Res (2014)

Bottom Line: Based on the luminescence spectra, luminescence lifetimes and optical parameters, which were calculated using the simplified Judd-Ofelt theory, correlations between the Gd2O3 nanoparticles morphology and Eu(3+) ions luminescence were established, and allowed to predict the theoretical maximum quantum efficiency to reach from 61 to 98 %.With the use of a tunable femtosecond laser system and the Z-scan measurement technique, the values of the effective two-photon absorption cross-section in the wavelength range from 550 to 1,200 nm were also calculated.The nonlinear optical measurements revealed maximum multi-photon absorption in the wavelength range from 600 to 750 nm.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.

ABSTRACT
The synthesis, morphological characterization, and optical properties of colloidal, Eu(III) doped Gd2O3 nanoparticles with different sizes and shapes are presented. Utilizing wet chemical techniques and various synthesis routes, we were able to obtain spherical, nanodisk, nanotripod, and nanotriangle-like morphology of Gd2O3:Eu(3+) nanoparticles. Various concentrations of Eu(3+) ions in the crystal matrix of the nanoparticles were tested in order to establish the levels at which the concentration quenching effect is negligible. Based on the luminescence spectra, luminescence lifetimes and optical parameters, which were calculated using the simplified Judd-Ofelt theory, correlations between the Gd2O3 nanoparticles morphology and Eu(3+) ions luminescence were established, and allowed to predict the theoretical maximum quantum efficiency to reach from 61 to 98 %. We have also discussed the impact of the crystal structure of Gd2O3 nanoparticles, as well as coordinating environment of luminescent ions located at the surface, on the emission spectra. With the use of a tunable femtosecond laser system and the Z-scan measurement technique, the values of the effective two-photon absorption cross-section in the wavelength range from 550 to 1,200 nm were also calculated. The nonlinear optical measurements revealed maximum multi-photon absorption in the wavelength range from 600 to 750 nm.

No MeSH data available.


TEM images and SAED patterns for Gd2O3:Eu3+ NPs synthesized following Paik et al. (2013) obtained after 45 min (a), 1.5 h (b), and 3.5 h (c) time of synthesis. XRD patterns of nanotriangle, intermediate form, and nanotripod shaped Gd2O3:Eu3+ NPs compared with standard (JCPDS 12-797) pattern of cubic Gd2O3 (d)
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Fig2: TEM images and SAED patterns for Gd2O3:Eu3+ NPs synthesized following Paik et al. (2013) obtained after 45 min (a), 1.5 h (b), and 3.5 h (c) time of synthesis. XRD patterns of nanotriangle, intermediate form, and nanotripod shaped Gd2O3:Eu3+ NPs compared with standard (JCPDS 12-797) pattern of cubic Gd2O3 (d)

Mentions: Figures 1 and 2 present the morphological and crystallographic characterization of Eu3+-doped Gd2O3 NPs obtained by the synthesis protocols described by (Cao 2004) and (Paik et al. 2013), respectively. As can be seen from Fig. 1, when low volumes of coordinating solvents are used and no Li+ ions are added to the reaction, the synthesis results in formation of nanospheres and nanodiscs. In particular, smaller amount of Gd3+ and Eu3+ acetates (1 mM) with respect to the constant coordinating solvents volume results in formation of small, spherical Gd2O3 NPs with average sizes below 5 nm (Fig. 1a). The increase of the lanthanide acetates amount (2 mM) results in formation of thin nanodiscs with average dimensions ~10 nm/~1.3 nm (Fig. 1b). Based on the SAED patterns (insets in Fig. 1a, b), and comparisons of XRD patterns for nanospheres and nanodiscs (Fig. 1c) with standard (JCPDS 12-797) pattern of cubic Gd2O3, we have assigned the obtained NPs to the Gd2O3 cubic phase. We have observed significant broadening of the XRD peaks and diffraction rings diameters related to the lattice plane spacing, being a result of small sizes of the NPs.Fig. 1


Morphology- and size-dependent spectroscopic properties of Eu(3+)-doped Gd2O3 colloidal nanocrystals.

Wawrzynczyk D, Nyk M, Bednarkiewicz A, Strek W, Samoc M - J Nanopart Res (2014)

TEM images and SAED patterns for Gd2O3:Eu3+ NPs synthesized following Paik et al. (2013) obtained after 45 min (a), 1.5 h (b), and 3.5 h (c) time of synthesis. XRD patterns of nanotriangle, intermediate form, and nanotripod shaped Gd2O3:Eu3+ NPs compared with standard (JCPDS 12-797) pattern of cubic Gd2O3 (d)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig2: TEM images and SAED patterns for Gd2O3:Eu3+ NPs synthesized following Paik et al. (2013) obtained after 45 min (a), 1.5 h (b), and 3.5 h (c) time of synthesis. XRD patterns of nanotriangle, intermediate form, and nanotripod shaped Gd2O3:Eu3+ NPs compared with standard (JCPDS 12-797) pattern of cubic Gd2O3 (d)
Mentions: Figures 1 and 2 present the morphological and crystallographic characterization of Eu3+-doped Gd2O3 NPs obtained by the synthesis protocols described by (Cao 2004) and (Paik et al. 2013), respectively. As can be seen from Fig. 1, when low volumes of coordinating solvents are used and no Li+ ions are added to the reaction, the synthesis results in formation of nanospheres and nanodiscs. In particular, smaller amount of Gd3+ and Eu3+ acetates (1 mM) with respect to the constant coordinating solvents volume results in formation of small, spherical Gd2O3 NPs with average sizes below 5 nm (Fig. 1a). The increase of the lanthanide acetates amount (2 mM) results in formation of thin nanodiscs with average dimensions ~10 nm/~1.3 nm (Fig. 1b). Based on the SAED patterns (insets in Fig. 1a, b), and comparisons of XRD patterns for nanospheres and nanodiscs (Fig. 1c) with standard (JCPDS 12-797) pattern of cubic Gd2O3, we have assigned the obtained NPs to the Gd2O3 cubic phase. We have observed significant broadening of the XRD peaks and diffraction rings diameters related to the lattice plane spacing, being a result of small sizes of the NPs.Fig. 1

Bottom Line: Based on the luminescence spectra, luminescence lifetimes and optical parameters, which were calculated using the simplified Judd-Ofelt theory, correlations between the Gd2O3 nanoparticles morphology and Eu(3+) ions luminescence were established, and allowed to predict the theoretical maximum quantum efficiency to reach from 61 to 98 %.With the use of a tunable femtosecond laser system and the Z-scan measurement technique, the values of the effective two-photon absorption cross-section in the wavelength range from 550 to 1,200 nm were also calculated.The nonlinear optical measurements revealed maximum multi-photon absorption in the wavelength range from 600 to 750 nm.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.

ABSTRACT
The synthesis, morphological characterization, and optical properties of colloidal, Eu(III) doped Gd2O3 nanoparticles with different sizes and shapes are presented. Utilizing wet chemical techniques and various synthesis routes, we were able to obtain spherical, nanodisk, nanotripod, and nanotriangle-like morphology of Gd2O3:Eu(3+) nanoparticles. Various concentrations of Eu(3+) ions in the crystal matrix of the nanoparticles were tested in order to establish the levels at which the concentration quenching effect is negligible. Based on the luminescence spectra, luminescence lifetimes and optical parameters, which were calculated using the simplified Judd-Ofelt theory, correlations between the Gd2O3 nanoparticles morphology and Eu(3+) ions luminescence were established, and allowed to predict the theoretical maximum quantum efficiency to reach from 61 to 98 %. We have also discussed the impact of the crystal structure of Gd2O3 nanoparticles, as well as coordinating environment of luminescent ions located at the surface, on the emission spectra. With the use of a tunable femtosecond laser system and the Z-scan measurement technique, the values of the effective two-photon absorption cross-section in the wavelength range from 550 to 1,200 nm were also calculated. The nonlinear optical measurements revealed maximum multi-photon absorption in the wavelength range from 600 to 750 nm.

No MeSH data available.