Ultrafast synthesis of bifunctional Er³⁺/Yb³⁺-codoped NaBiF₄ upconverting nanoparticles for nanothermometer and optical heater

Du, Peng,Luo, Laihui,Huang, Xiaoyong,Yu, Jae Su Elsevier 2018 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.514 No.-

<P><B>Abstract</B></P> <P>We reported a simple and ultrafast route to synthesize the bifunctional Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>-codoped NaBiF<SUB>4</SUB> upconverting nanoparticles. It was found that the phase composition and microstructure of the prepared samples were strongly dependent on the NH<SUB>4</SUB>F content. When the NH<SUB>4</SUB>F content was 14 mmol, after 1 min reaction at room temperature, the resultant compounds exhibited pure single phase and were composed of uniform spherical nanoparticles. Under 980 nm light irradiation, the synthesized nanoparticles emitted visible emissions originating from the intra-4f transitions of Er<SUP>3+</SUP> ions and the involved upconversion luminescence mechanism was associated with the typical two-photon process. With the aid of the fluorescence intensity ratio technique, the optical thermometric behaviors of the studied nanoparticle based on the (<SUP>2</SUP>H<SUB>11/2</SUB>,<SUP>4</SUP>S<SUB>3/2</SUB>) thermally-coupled levels in the temperature range of 303–483 K were systematically analyzed and the maximum sensor sensitivity was determined to be about 0.0057 K<SUP>−1</SUP> at 483 K. Furthermore, the internal heating properties of the resultant nanoparticles induced by the laser power source were also studied. With elevating the pump power from 159 to 658 mW, the temperature of the upconverting nanoparticles was improved from 304 to 464 K. These results suggest that the Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>-codoped NaBiF<SUB>4</SUB> upconverting nanoparticles are promising bifunctional luminescent materials for nanothermometer and optical heater applications.</P> <P><B>Graphical abstract</B></P> <P>Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>-codoped NaBiF<SUB>4</SUB> nanoparticles were successfully synthesized <I>via</I> a one-minute reaction process at room temperature. The resultant nanoparticles did not possess superior UC emission properties but also exhibited promising applications in temperature sensor and optical heater.</P> <P>[DISPLAY OMISSION]</P>

Facile synthesis of bifunctional Eu³⁺-activated NaBiF₄ red-emitting nanoparticles for simultaneous white light-emitting diodes and field emission displays

Du, Peng,Huang, Xiaoyong,Yu, Jae Su Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.337 No.-

<P><B>Abstract</B></P> <P>A series of novel Eu<SUP>3+</SUP>-activated NaBiF<SUB>4</SUB> nanoparticles were synthesized by an ultra-fast chemical precipitate method at room temperature. Under the excitation of 394 nm, all the compounds emitted glaring red emissions originating from the intra-4f transitions of Eu<SUP>3+</SUP> ions. The optimal doping concentration was found to be 40 mol% and the concentration quenching mechanism was dominated by dipole–dipole interaction. The temperature-dependent photoluminescence emission spectra revealed that the resultant nanoparticles possessed admirable thermal stability with an activation energy of 0.237 eV. The internal quantum efficiency of the synthesized nanoparticles was estimated to be as high as 73.1%. Furthermore, the optical transition parameters of Eu<SUP>3+</SUP> ions were calculated using a facile method based on the Judd-Ofelt theory to explore the local structure environment around the Eu<SUP>3+</SUP> ions in the NaBiF<SUB>4</SUB> host lattice. Additionally, the packaged light-emitting diode (LED) device, which was composed of a near-ultraviolet LED chip, synthesized nanoparticles and commercial blue-emitting/green-emitting phosphors, exhibited brightly white light with high color rendering index of 88.2 and proper correlated color temperature of 6851 K. Ultimately, the studied nanoparticles also had splendid cathodoluminescence properties. These results suggest that the Eu<SUP>3+</SUP>-activated NaBiF<SUB>4</SUB> nanoparticles were promising bifunctional materials for simultaneous white LEDs and field emission displays.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NaBiF<SUB>4</SUB>:Eu<SUP>3+</SUP> nanoparticles were synthesized by an ultra-fast method. </LI> <LI> UV excitation induced bright red emissions with quantum efficiency of 73.1%. </LI> <LI> They possessed good thermal stability with activation energy of 0.237 eV. </LI> <LI> The cathodoluminescence properties of the nanoparticles were also studied. </LI> <LI> LED devices were fabricated by using the nanoparticles and UV LED chips. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>EL spectrum of the fabricated WLEDs device. Inset illustrates the schematic diagram for the fabrication of LED device. Luminescent images of the prepared WLEDs device without and with input current.</P> <P>[DISPLAY OMISSION]</P>

Ethylene glycol assisted rapid preparation of NaEuF₄ nanorods with splendid thermal stability for indoor illumination and optical displays

Du, Peng,Huang, Xiaoyong,Yu, Jae Su Elsevier 2018 Dyes and pigments Vol.153 No.-

<P><B>Abstract</B></P> <P>The NaEuF<SUB>4</SUB> nanorods were prepared by an ultra-rapid reaction route at room temperature. Under the excitation of near-ultraviolet (NUV) light, the synthesized nanorods emitted visible red emission, which is ascribed to the characteristic emission of Eu<SUP>3+</SUP> ions, with high color purity of 90.2%. To get deeper insight into the local structure circumstance of Eu<SUP>3+</SUP> ions, a theoretical calculation based on the Judd-Ofelt theory was performed to evaluate the intensity parameters and the larger Ω<SUB>2</SUB> suggested that the Eu<SUP>3+</SUP> ions occupied the low symmetry sites in the NaEuF<SUB>4</SUB> host lattices. The temperature-dependent photoluminescence emission spectra were recorded to examine the thermal stability of the resultant samples and the activation energy was determined to be 0.208 eV. To test the potential practicability of the studied samples in solid-state lighting, a light-emitting diode (LED) device was fabricated. Under a forward bias current of 100 mA, the fabricated LED device emitted dazzling white light with high color rendering index of 90.3, suitable correlated color temperature of 6793 K and good color coordinate of (0.313,0.297). In addition, the cathodoluminescence properties of the NaEuF<SUB>4</SUB> nanorods were systematically studied to explore their applications in field emission displays.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The NaEuF<SUB>4</SUB> nanorods were synthesized by an ultrafast route at room temperature. </LI> <LI> The prepared samples emitted dazzling red emission under NUV light excitation. </LI> <LI> The resultant NaEuF<SUB>4</SUB> nanorods possessed splendid thermal stability. </LI> <LI> The local structure environment properties around the Eu<SUP>3+</SUP> ions were verified by Judd-Ofelt theory. </LI> <LI> The fabricated WLED device possessed admirable optical performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Facile synthesis of uniform NaEuF<SUB>4</SUB> red-emitting nanorods at room temperature for white light-emitting diodes and optical displays.</P> <P>[DISPLAY OMISSION]</P>

Realizing highly efficient multicolor tunable emissions from Tb³⁺ and Eu³⁺ co-doped CaGd₂(WO₄)₄ phosphors via energy transfer by single ultraviolet excitation for lighting and display applications

Huang, Xiaoyong,Li, Bin,Du, Peng,Guo, Heng,Cao, Renping,Yu, Jae Su,Wang, Kai,Sun, Xiao Wei Elsevier 2018 Dyes and pigments Vol.151 No.-

<P><B>Abstract</B></P> <P>In this paper, we reported on multicolor emission tuning in Tb<SUP>3+</SUP> and Eu<SUP>3+</SUP> co-doped CaGd<SUB>2</SUB>(WO<SUB>4</SUB>)<SUB>4</SUB> phosphors prepared by a traditional high-temperature solid-state reaction. Upon 380 nm ultraviolet excitation, the emission color of CaGd<SUB>2</SUB>(WO<SUB>4</SUB>)<SUB>4</SUB>:Tb<SUP>3+</SUP>,Eu<SUP>3+</SUP> phosphors can be readily tuned from green to yellow, orange and finally to pure red through varying the concentration ratio of Eu<SUP>3+</SUP> and Tb<SUP>3+</SUP> ions. The energy transfer mechanism from Tb<SUP>3+</SUP> to Eu<SUP>3+</SUP> was systematically investigated by photoluminescence spectra, luminescence decay times, and time-resolved spectra. The internal quantum efficiencies of these phosphors were measured, and their thermal stability was also studied. A prototype white light-emitting diode (LED) device was fabricated by using an ultraviolet chip combined with a blend of blue-emitting BaMgAl<SUB>10</SUB>O<SUB>l7</SUB>:Eu<SUP>2+</SUP> phosphors, green-emitting BaSrSiO<SUB>4</SUB>:Eu<SUP>2+</SUP> phosphors, and red-emitting CaGd<SUB>2</SUB>(WO<SUB>4</SUB>)<SUB>4</SUB>:50%Tb<SUP>3+</SUP>,50%Eu<SUP>3+</SUP> phosphors. All the results indicate that the CaGd<SUB>2</SUB>(WO<SUB>4</SUB>)<SUB>4</SUB>:Tb<SUP>3+</SUP>,Eu<SUP>3+</SUP> has great potential application in lighting and displays.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CaGd<SUB>2</SUB>(WO<SUB>4</SUB>)<SUB>4</SUB>:Tb<SUP>3+</SUP>,Eu<SUP>3+</SUP> showed efficient energy-transfer from Tb<SUP>3+</SUP> to Eu<SUP>3+</SUP>. </LI> <LI> CaGd<SUB>2</SUB>(WO<SUB>4</SUB>)<SUB>4</SUB>:Tb<SUP>3+</SUP>,Eu<SUP>3+</SUP> exhibited tunable color emission under 380 nm excitation. </LI> <LI> The energy-transfer mechanism was studied in detail. </LI> <LI> Quantum efficiency and thermal stability were investigated. </LI> <LI> The proof-of-concept LED lamps were fabricated by employing phosphors and UV LEDs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Automatic Data Distribution in Large-scale OLTP Applications

Xiaoyan Wang,Xu Fan,Jinchuan Chen,Xiaoyong Du 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.4

Genetic signature of strong recent positive selection at interleukin-32 gene in goat

Akhtar Rasool Asif,Sumayyah Qadri,Nabeel Ijaz,Ruheena Javed,Abdur Rahman Ansari,Muhammd Awais,Muhammad Younus,Hasan Riaz,Xiaoyong Du 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.7

Objective: Identification of the candidate genes that play key roles in phenotypic variations can provide new information about evolution and positive selection. Interleukin (IL)-32 is involved in many biological processes, however, its role for the immune response against various diseases in mammals is poorly understood. Therefore, the current investigation was performed for the better understanding of the molecular evolution and the positive selection of single nucleotide polymorphisms in IL-32 gene. Methods: By using fixation index (FST) based method, IL-32 (9375) gene was found to be outlier and under significant positive selection with the provisional combined allocation of mean heterozygosity and FST. Using nucleotide sequences of 11 mammalian species from National Center for Biotechnology Information database, the evolutionary selection of IL-32 gene was determined using Maximum likelihood model method, through four models (M1a, M2a, M7, and M8) in Codeml program of phylogenetic analysis by maximum liklihood. Results: IL-32 is detected under positive selection using the FST simulations method. The phylogenetic tree revealed that goat IL-32 was in close resemblance with sheep IL-32. The coding nucleotide sequences were compared among 11 species and it was found that the goat IL-32 gene shared identity with sheep (96.54%), bison (91.97%), camel (58.39%), cat (56.59%), buffalo (56.50%), human (56.13%), dog (50.97%), horse (54.04%), and rabbit (53.41%) respectively. Conclusion: This study provides evidence for IL-32 gene as under significant positive selection in goat.