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Hydrothermal-assisted exfoliation of Y/Tb/Eu ternary layered rare-earth hydroxides into tens of micron-sized unilamellar nanosheets for highly oriented and color-tunable nano-phosphor films.

Zhu Q, Xu Z, Li JG, Li X, Qi Y, Sun X - Nanoscale Res Lett (2015)

Bottom Line: The intercalation of oleate anions led to extremely expanded interlayer distances (up to approximately 5.2 nm) of the LRH crystals and accordingly disordered stacking of the ab planes along the c-axis and also weakened interlayer interactions, without significantly damaging the ab plane.Highly [111]-oriented and approximately 100-nm thick oxide films of (Y0.96Tb x Eu0.04-x ) 2O3 (0 ≤ x ≤ 0.04) have been obtained through spin-coating of the exfoliated colloidal nanosheets on quartz substrate, followed by annealing at 800°C.Upon UV excitation at 266 nm, the oxide transparent films exhibit bright luminescence, with the color-tunable emission from red to orange, yellow, and then green by increasing the Tb(3+) content from x = 0 to 0.04.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, No. 3-11, Wenhua Road, Shenyang, Liaoning 110819 China.

ABSTRACT
Efficient exfoliation of well-crystallized (Y0.96Tb x Eu0.04-x )2(OH)5NO3 · nH2O (0 ≤ x ≤ 0.04) layered rare-earth hydroxide (LRH) crystals into tens of micron-sized unilamellar nanosheets has been successfully achieved by inserting water insoluble oleate anions (C17H33COO(-)) into the interlayer of the LRH via hydrothermal anion exchange at 120°C, followed by delaminating in toluene. The intercalation of oleate anions led to extremely expanded interlayer distances (up to approximately 5.2 nm) of the LRH crystals and accordingly disordered stacking of the ab planes along the c-axis and also weakened interlayer interactions, without significantly damaging the ab plane. As a consequence, the thickness of the LRH crystals increased from approximately 1 to 10 μm, exhibiting a behavior similar to that observed from the smectite clay in water. Highly [111]-oriented and approximately 100-nm thick oxide films of (Y0.96Tb x Eu0.04-x ) 2O3 (0 ≤ x ≤ 0.04) have been obtained through spin-coating of the exfoliated colloidal nanosheets on quartz substrate, followed by annealing at 800°C. Upon UV excitation at 266 nm, the oxide transparent films exhibit bright luminescence, with the color-tunable emission from red to orange, yellow, and then green by increasing the Tb(3+) content from x = 0 to 0.04.

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XRD patterns of the hydrothermal products and FE-SEM morphology of thex = 0.035 sample. (a) XRD patterns of the (Y0.96TbxEu0.04-x)2(OH)5NO3 · nH2O ( 0 ≤ x ≤ 0.04) LRH solid solutions hydrothermally synthesized at 180°C and (b) FE-SEM morphology of the x = 0.035 sample.
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Fig1: XRD patterns of the hydrothermal products and FE-SEM morphology of thex = 0.035 sample. (a) XRD patterns of the (Y0.96TbxEu0.04-x)2(OH)5NO3 · nH2O ( 0 ≤ x ≤ 0.04) LRH solid solutions hydrothermally synthesized at 180°C and (b) FE-SEM morphology of the x = 0.035 sample.

Mentions: Well-crystallized and ultra-large LRHs crystals can be synthesized by autoclaving mixed nitrate solution of the component rare-earths at 180°C to 200°C and in the presence of NH4NO3 mineralizer [25]. Figure 1a shows XRD patterns of the hydrothermal products with various amounts of Tb3+. A series of strong (00 l) reflections were observed to be characteristic of a layered phase, as previously reported for the Ln2(OH)5NO3 · nH2O LRHs (see Additional file 1: Table S1) [13-21]. A number of weak non-(00 l) reflections were also detected, indicating that the LRHs are ordered for their hydroxide main layers. The solid solutions were found to have similar lattice constants of a ~ 1.273, b ~ 0.715, and c ~ 1.800 nm, due to the small total content (4 at.%) of Tb3+ and Eu3+ and the similar sizes of the two kinds of ions (for eightfold coordination, and ). Figure 1b shows FE-SEM morphology of the x = 0.035 sample, where the crystals were observed to be uniform hexagons of ≥30 μm in lateral size and approximately 1 μm in thickness. The straight and sharp crystal edges with intersection angles of approximately 120° may suggest high crystallinity of the platelets. Similar morphologies were observed for the other Y/Tb/Eu combinations and are thus not shown.Figure 1


Hydrothermal-assisted exfoliation of Y/Tb/Eu ternary layered rare-earth hydroxides into tens of micron-sized unilamellar nanosheets for highly oriented and color-tunable nano-phosphor films.

Zhu Q, Xu Z, Li JG, Li X, Qi Y, Sun X - Nanoscale Res Lett (2015)

XRD patterns of the hydrothermal products and FE-SEM morphology of thex = 0.035 sample. (a) XRD patterns of the (Y0.96TbxEu0.04-x)2(OH)5NO3 · nH2O ( 0 ≤ x ≤ 0.04) LRH solid solutions hydrothermally synthesized at 180°C and (b) FE-SEM morphology of the x = 0.035 sample.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4385236&req=5

Fig1: XRD patterns of the hydrothermal products and FE-SEM morphology of thex = 0.035 sample. (a) XRD patterns of the (Y0.96TbxEu0.04-x)2(OH)5NO3 · nH2O ( 0 ≤ x ≤ 0.04) LRH solid solutions hydrothermally synthesized at 180°C and (b) FE-SEM morphology of the x = 0.035 sample.
Mentions: Well-crystallized and ultra-large LRHs crystals can be synthesized by autoclaving mixed nitrate solution of the component rare-earths at 180°C to 200°C and in the presence of NH4NO3 mineralizer [25]. Figure 1a shows XRD patterns of the hydrothermal products with various amounts of Tb3+. A series of strong (00 l) reflections were observed to be characteristic of a layered phase, as previously reported for the Ln2(OH)5NO3 · nH2O LRHs (see Additional file 1: Table S1) [13-21]. A number of weak non-(00 l) reflections were also detected, indicating that the LRHs are ordered for their hydroxide main layers. The solid solutions were found to have similar lattice constants of a ~ 1.273, b ~ 0.715, and c ~ 1.800 nm, due to the small total content (4 at.%) of Tb3+ and Eu3+ and the similar sizes of the two kinds of ions (for eightfold coordination, and ). Figure 1b shows FE-SEM morphology of the x = 0.035 sample, where the crystals were observed to be uniform hexagons of ≥30 μm in lateral size and approximately 1 μm in thickness. The straight and sharp crystal edges with intersection angles of approximately 120° may suggest high crystallinity of the platelets. Similar morphologies were observed for the other Y/Tb/Eu combinations and are thus not shown.Figure 1

Bottom Line: The intercalation of oleate anions led to extremely expanded interlayer distances (up to approximately 5.2 nm) of the LRH crystals and accordingly disordered stacking of the ab planes along the c-axis and also weakened interlayer interactions, without significantly damaging the ab plane.Highly [111]-oriented and approximately 100-nm thick oxide films of (Y0.96Tb x Eu0.04-x ) 2O3 (0 ≤ x ≤ 0.04) have been obtained through spin-coating of the exfoliated colloidal nanosheets on quartz substrate, followed by annealing at 800°C.Upon UV excitation at 266 nm, the oxide transparent films exhibit bright luminescence, with the color-tunable emission from red to orange, yellow, and then green by increasing the Tb(3+) content from x = 0 to 0.04.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, No. 3-11, Wenhua Road, Shenyang, Liaoning 110819 China.

ABSTRACT
Efficient exfoliation of well-crystallized (Y0.96Tb x Eu0.04-x )2(OH)5NO3 · nH2O (0 ≤ x ≤ 0.04) layered rare-earth hydroxide (LRH) crystals into tens of micron-sized unilamellar nanosheets has been successfully achieved by inserting water insoluble oleate anions (C17H33COO(-)) into the interlayer of the LRH via hydrothermal anion exchange at 120°C, followed by delaminating in toluene. The intercalation of oleate anions led to extremely expanded interlayer distances (up to approximately 5.2 nm) of the LRH crystals and accordingly disordered stacking of the ab planes along the c-axis and also weakened interlayer interactions, without significantly damaging the ab plane. As a consequence, the thickness of the LRH crystals increased from approximately 1 to 10 μm, exhibiting a behavior similar to that observed from the smectite clay in water. Highly [111]-oriented and approximately 100-nm thick oxide films of (Y0.96Tb x Eu0.04-x ) 2O3 (0 ≤ x ≤ 0.04) have been obtained through spin-coating of the exfoliated colloidal nanosheets on quartz substrate, followed by annealing at 800°C. Upon UV excitation at 266 nm, the oxide transparent films exhibit bright luminescence, with the color-tunable emission from red to orange, yellow, and then green by increasing the Tb(3+) content from x = 0 to 0.04.

No MeSH data available.


Related in: MedlinePlus