Surface effect of nanocrystals doped with rare-earth ions enriched on surface and its application in upconversion luminescence

En-Jie, He; Liu, Ning; Zhang, Maolian; Qin, Yanfu; Guan, Banggui; Li, Yong; Guo, Minghui

doi:10.1088/1674-1056/21/7/073201

Cited by 6 publications

(5 citation statements)

References 23 publications

(10 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…38 The larger the surface-to-volume ratio is, the more Er 3+ /Ho 3+ ions are located at/near the surface of the nanoparticles relative to the Er 3+ /Ho 3+ ions in the core. 39,40 Therefore, the samples prepared with 0.1 g EDTA have more Er 3+ /Ho 3+ ions at/near the surface. NaCe(MoO 4 ) 2 : 2%Er 3+ , 5% Yb 3+ with the assistance of 0.1 g EDTA is slightly smaller than those prepared in the EDTA-absence, which is attributed to the smaller sizes of the Er 3+ (0.0945 nm) compared to Ce 3+ (0.107 nm).…”

Section: Resultsmentioning

confidence: 99%

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er³⁺/Ho³⁺-Yb³⁺ co-doped NaCe(MoO₄)₂ phosphor

Yang

et al. 2015

RSC Adv.

View full text Add to dashboard Cite

Uniform and well-crystallized NaCe(MoO 4 ) 2 : Er 3+ /Ho 3+ , Yb 3+ up-conversion (UC) phosphors have been successfully synthesized by a facile hydrothermal route at 180 o C for 12 h at pH=9. The crystalline phase, size and morphology were systematically characterized using powder X-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM). The experimental results showed that the ethylene diamine tetraacetic acid (EDTA) was a key parameter which not only determined their spacial arrangement, but also affected the size distributions of the final products.Moreover, we found that EDTA could tune the band edge absorption of molybdate system by changing the lattice parameters, so as to realize their bicolour tunable luminescence of Er 3+ /Ho 3+ -Yb 3+ co-doped NaCe(MoO 4 ) 2 for the first time. Studies of the behavior as a function of dopant concentration were all described. The different UC mechanism of the samples with and without EDTA were systematically depicted as well. It was found that an innovative route to increase the green UC emission and simultaneously suppress red UC emission in Er 3+ /Ho 3+ -Yb 3+ co-doped NaCe(MoO 4 ) 2 prepared with the assistance of 0.1 g EDTA, which enhanced the efficiency of the single green color.Since the UC luminescence of rare-earth (RE) ions was discovered by Auzel in the mid-1960s, 1-2 it has been the focus of much research. Potential applications include solar cells, 3-6 novel display technologies, 7-9 inks for secure printing 10 and, more recently, biophysics. 11-13 Their advantages include near-infrared (NIR) excitation, low cytotoxicity, weak autofluorescence, high chemical stability, and low photobleaching, which make them more desirable than conventional organic dyes or quantum dots for bioimaging application. 14-17 The photoluminescence emission from rare earth doped materials arises due to the transitions within the 4f n energy manifolds which are forbidden because of the electric dipole selection rule but these are allowed due to the mixing of configurations having opposite parity. One of the most exciting properties of these materials is frequency UC where two or more photons having relatively low energy are absorbed by the material and subsequently converted to a higher energy photon (this is an anti-Stokes process). However, the commonly investigated lanthanide activators such as Er 3+ and Ho 3+ ions contain abundant metastable excited states, and the dominant emission usually lies in the non-green region with relatively low green emission intensity. Hence, a strategy to boost the green emission intensity will be useful for UC applications.It is well known that lattice parameter is the fundamental factor that affects the luminescence property. [18][19] During the hydrothermal process, the introduction of EDTA with functional groups into the reaction system can effectively change the band edge absorption of MoO 4 2of the final product by changing the lattice parameters, which makes effort to build energy level match conditions between relati...

show abstract

Section: Resultsmentioning

confidence: 99%

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er³⁺/Ho³⁺-Yb³⁺ co-doped NaCe(MoO₄)₂ phosphor

Yang

et al. 2015

RSC Adv.

View full text Add to dashboard Cite

show abstract

“…This is a facile strategy to tuning the phase and morphology, which is helpful for further crystal-design and morphology-controlled synthesis of other nanocrystals. [36] Moreover, these obtained products present different emission spectra, which makes it possible to tune the UC fluorescence of the nanocrystals. The emission spectra tuning will enable these UC nanomaterials to offer promising application prospects in many fields, such as 3D displays, solar cells, and multiplexing bioassays.…”

Section: Discussionmentioning

confidence: 99%

Phase transformation and morphology tuning of β -NaYF ₄ :Yb ³⁺ ,Er ³⁺ nanocrystals through K ⁺ ions codoping

et al. 2015

View full text Add to dashboard Cite

In this work, a simple method to modulate the crystal phase and morphology with a large amount of K+ ions codoping is proposed. The phase changes to the mixture of β-NaYF4 and β-KYF4 with increasing the content of K+ ions to 80 mol%. When it exceeds 80 mol%, β-NaYF4 disappears gradually and β-KYF4 dominates with a poor crystalline. In addition, the morphology changes from nanosphere to nanoplate, and then to nanoprism, which indicates that a higher content of K+ ions favors the growth rates along [0001] than the [10-10] of the nanocrystals. Additionally, the upconversion (UC) luminescence properties and the ratio of red/green (R/G) UC intensity of samples with different phases and morphologies are detected, which makes it possible to tune the UC fluorescence by varying the concentration of K+ ions.

show abstract

“…[25,26] The mechanisms of Yb 3+ as a sensitizer and Tm 3+ as an activator UC luminescence system have been discussed widely in many researches. [27][28][29] The relative diagram can be seen in Fig. 6.…”

Section: Tg-dsc Analysis Of the Precursorsmentioning

confidence: 99%

Hydrothermal synthesis of Yb ³⁺ , Tm ³⁺ co-doped Gd ₆ MoO ₁₂ and its upconversion properties

Di¹,

Sun²,

Xu³

et al. 2015

Chinese Phys. B

View full text Add to dashboard Cite

Yb 3+ , Tm 3+ co-doped Gd 6 MoO 12 phosphors with different morphologies are prepared by the hydrothermal method. The dendrites present different morphologies (including hexagonal prisms, spindles, and spheres) after changing the pH value and edetate disodium (EDTA) usage. It is found that each of the two factors plays a crucial role in forming different morphologies.The up-conversion (UC) luminescence is studied. Under 980-nm semiconductor laser excitation, relatively strong blue emission and weak red emission are observed. Finally, the effect of pumping power on the UC luminescence properties and the level diagram mechanism of Gd 6 MoO 12 :Yb 3+ /Tm 3+ phosphor are also discussed.

show abstract

Surface effect of nanocrystals doped with rare-earth ions enriched on surface and its application in upconversion luminescence

Cited by 6 publications

References 23 publications

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er³⁺/Ho³⁺-Yb³⁺ co-doped NaCe(MoO₄)₂ phosphor

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er³⁺/Ho³⁺-Yb³⁺ co-doped NaCe(MoO₄)₂ phosphor

Phase transformation and morphology tuning of β -NaYF ₄ :Yb ³⁺ ,Er ³⁺ nanocrystals through K ⁺ ions codoping

Hydrothermal synthesis of Yb ³⁺ , Tm ³⁺ co-doped Gd ₆ MoO ₁₂ and its upconversion properties

Contact Info

Product

Resources

About

Surface effect of nanocrystals doped with rare-earth ions enriched on surface and its application in upconversion luminescence

Cited by 6 publications

References 23 publications

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er3+/Ho3+-Yb3+ co-doped NaCe(MoO4)2 phosphor

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er3+/Ho3+-Yb3+ co-doped NaCe(MoO4)2 phosphor

Phase transformation and morphology tuning of β -NaYF 4 :Yb 3+ ,Er 3+ nanocrystals through K + ions codoping

Hydrothermal synthesis of Yb 3+ , Tm 3+ co-doped Gd 6 MoO 12 and its upconversion properties

Contact Info

Product

Resources

About

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er³⁺/Ho³⁺-Yb³⁺ co-doped NaCe(MoO₄)₂ phosphor

Controlled morphology and EDTA-induced pure green upconversion luminescence of Er³⁺/Ho³⁺-Yb³⁺ co-doped NaCe(MoO₄)₂ phosphor

Phase transformation and morphology tuning of β -NaYF ₄ :Yb ³⁺ ,Er ³⁺ nanocrystals through K ⁺ ions codoping

Hydrothermal synthesis of Yb ³⁺ , Tm ³⁺ co-doped Gd ₆ MoO ₁₂ and its upconversion properties