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Enhancement of luminescence in white emitting strontium fluoride core @ calcium fluoride shell nanoparticles.

Kumam N, Singh NP, Singh LP, Srivastava SK - Nanoscale Res Lett (2015)

Bottom Line: The size of the nanoparticles for core (SrF2:3Dy) is found to increase when core is covered by shell (CaF2).The calculated correlate colour temperature (CCT) values for SrF2:3Dy, SrF2:3Dy@CaF2 (1:0.05), SrF2:3Dy@CaF2 (1:1) and SrF2:3Dy@CaF2 (1:2) are 5475, 5476, 5384 and 5525 K, respectively, which lie in the cold white region.Graphical abstract White light emitting homonanostructure material SrF2:3Dy@CaF2(core@shell).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Manipur University, Imphal, 795003, India.

ABSTRACT
Synthesis of lanthanide-doped fluoride SrF2:3Dy and SrF2:3Dy@CaF2 nanoparticles with different ratios of core to shell (1:0.5, 1:1 and 1:2) has been carried out by employing ethylene glycol route. X-ray diffraction (XRD) patterns reveal that the structure of the prepared nanoparticles was of cubical shape, which is also evident in TEM images. The size of the nanoparticles for core (SrF2:3Dy) is found to increase when core is covered by shell (CaF2). It is also evident from Fourier transform infrared spectroscopy (FTIR) that ethylene glycol successfully controls the growth and acts as a shape modifier by regulating growth rate. In the photoluminescence investigation, emission spectra of SrF2:3Dy is found to be highly enhanced when SrF2:3Dy is covered by CaF2 due to the decrease of cross relaxation amongst the Dy(3+)-Dy(3+) ions. Such type of enhancement of luminescence in homonanostructure SrF2:3Dy@CaF2 (core@shell) has not been studied so far, to the best of the authors' knowledge. This luminescent material exhibits prominently white light emitting properties as shown by the Commission Internationale d'Eclairage (CIE) chromaticity diagram. The calculated correlate colour temperature (CCT) values for SrF2:3Dy, SrF2:3Dy@CaF2 (1:0.05), SrF2:3Dy@CaF2 (1:1) and SrF2:3Dy@CaF2 (1:2) are 5475, 5476, 5384 and 5525 K, respectively, which lie in the cold white region. Graphical abstract White light emitting homonanostructure material SrF2:3Dy@CaF2(core@shell).

No MeSH data available.


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XRD pattern of pure, doped (3 at.% Dy3+ ion) SrF2 core and CaF2 shell at different ratios of shell
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Fig1: XRD pattern of pure, doped (3 at.% Dy3+ ion) SrF2 core and CaF2 shell at different ratios of shell

Mentions: Figure 1 shows the XRD pattern of SrF2, SrF2:3Dy and SrF2:3Dy@CaF2 at two different ratios of shell (1:1 and 1:2). All the peaks pattern for pure and SrF2:3Dy can be index with the Joint Committee on Powder Diffraction Standards (JCPDS) card number 06-0262 having cubical structure with space group Fm3m (225). In case of SrF2:3Dy@CaF2 core-shell, the peak patterns are found coexisting for both SrF2 and CaF2 phases, indicating the CaF2 coated on the SrF2.The star mark in the Fig. 1 indicates the SrF2 phase,and the hutch mark indicates the CaF2 phases. For CaF2, the peaks patterns are found to be face centre cubical structure with space group Fm3m (225) (JCPDS No. 35-0816). All the prepared samples are found to be crystalline structure, and there is no extra impurity peaks from the precursors of core SrF2 and shell CaF2. The lattice parameter and unit cell volume of the prepared samples are given in the Table 1. Williamson-Hall model [20] has been used to calculate the microstrain (ε) for the system under study.Fig. 1


Enhancement of luminescence in white emitting strontium fluoride core @ calcium fluoride shell nanoparticles.

Kumam N, Singh NP, Singh LP, Srivastava SK - Nanoscale Res Lett (2015)

XRD pattern of pure, doped (3 at.% Dy3+ ion) SrF2 core and CaF2 shell at different ratios of shell
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4554543&req=5

Fig1: XRD pattern of pure, doped (3 at.% Dy3+ ion) SrF2 core and CaF2 shell at different ratios of shell
Mentions: Figure 1 shows the XRD pattern of SrF2, SrF2:3Dy and SrF2:3Dy@CaF2 at two different ratios of shell (1:1 and 1:2). All the peaks pattern for pure and SrF2:3Dy can be index with the Joint Committee on Powder Diffraction Standards (JCPDS) card number 06-0262 having cubical structure with space group Fm3m (225). In case of SrF2:3Dy@CaF2 core-shell, the peak patterns are found coexisting for both SrF2 and CaF2 phases, indicating the CaF2 coated on the SrF2.The star mark in the Fig. 1 indicates the SrF2 phase,and the hutch mark indicates the CaF2 phases. For CaF2, the peaks patterns are found to be face centre cubical structure with space group Fm3m (225) (JCPDS No. 35-0816). All the prepared samples are found to be crystalline structure, and there is no extra impurity peaks from the precursors of core SrF2 and shell CaF2. The lattice parameter and unit cell volume of the prepared samples are given in the Table 1. Williamson-Hall model [20] has been used to calculate the microstrain (ε) for the system under study.Fig. 1

Bottom Line: The size of the nanoparticles for core (SrF2:3Dy) is found to increase when core is covered by shell (CaF2).The calculated correlate colour temperature (CCT) values for SrF2:3Dy, SrF2:3Dy@CaF2 (1:0.05), SrF2:3Dy@CaF2 (1:1) and SrF2:3Dy@CaF2 (1:2) are 5475, 5476, 5384 and 5525 K, respectively, which lie in the cold white region.Graphical abstract White light emitting homonanostructure material SrF2:3Dy@CaF2(core@shell).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Manipur University, Imphal, 795003, India.

ABSTRACT
Synthesis of lanthanide-doped fluoride SrF2:3Dy and SrF2:3Dy@CaF2 nanoparticles with different ratios of core to shell (1:0.5, 1:1 and 1:2) has been carried out by employing ethylene glycol route. X-ray diffraction (XRD) patterns reveal that the structure of the prepared nanoparticles was of cubical shape, which is also evident in TEM images. The size of the nanoparticles for core (SrF2:3Dy) is found to increase when core is covered by shell (CaF2). It is also evident from Fourier transform infrared spectroscopy (FTIR) that ethylene glycol successfully controls the growth and acts as a shape modifier by regulating growth rate. In the photoluminescence investigation, emission spectra of SrF2:3Dy is found to be highly enhanced when SrF2:3Dy is covered by CaF2 due to the decrease of cross relaxation amongst the Dy(3+)-Dy(3+) ions. Such type of enhancement of luminescence in homonanostructure SrF2:3Dy@CaF2 (core@shell) has not been studied so far, to the best of the authors' knowledge. This luminescent material exhibits prominently white light emitting properties as shown by the Commission Internationale d'Eclairage (CIE) chromaticity diagram. The calculated correlate colour temperature (CCT) values for SrF2:3Dy, SrF2:3Dy@CaF2 (1:0.05), SrF2:3Dy@CaF2 (1:1) and SrF2:3Dy@CaF2 (1:2) are 5475, 5476, 5384 and 5525 K, respectively, which lie in the cold white region. Graphical abstract White light emitting homonanostructure material SrF2:3Dy@CaF2(core@shell).

No MeSH data available.


Related in: MedlinePlus