A green and facile method using jet cavitation (JC) was utilized to prepare few layer graphene (FLG) derived from artificial graphite delamination without adding any strong acids and oxidants. The JC method not only provides high quality FLG with high yield but also demonstrate excellent electrochemical performance as anode materials for Li-ion batteries. Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) as well as BET isotherms and XPS are carried out in this study. The results of atomic force microscopy (AFM) further revealed that up to 85% of the prepared FLG were less than 10 layers. This exfoliation process happened mainly due to the cavitation-induced intensive tensile stress acting on the layered materials. Electrochemical measurements demonstrate that graphite anode delivered only 240 mAh/g while FLG anode achieved more than 322 mAh/g at 5C rate test. These results indicate that JC method not only paves the way for cheaper and safer production of graphene but also holds great potential applications in energy-related technology.

New blue-emitting phosphor, SrCa2MgSi2O8: Eu2+ (SCMSO: Eu2+), was synthesized by a solid state reaction. For further discussion, a series of analysis were performed such as photoluminescence excitation and emission spectra, diffuse reflectance spectra, thermal quenching, decay lifetime and electroluminescence to identify the luminescent properties of SrCa2MgSi2O8: Eu2+ phosphors. The SCMSO: Eu2+ displays broad excitation spectra ranging from 250-450 nm, and intend emission intensity at 469 nm under lambda(ex) = 360 nm. The optimum Eu2+ concentration of SCMSO was 10 mol%. The luminescence decay lifetimes of SCMSO: Eu2+ phosphors were measured to be 474.1-540.4 ns. The blue-emitting SrCa2MgSi2O8: 10% Eu2+ phosphors fabricated with commercial red-and green-emitting phosphor integrating white LED, excited with near UV LED chip (lambda(ex) = 390 nm), and shows excellent color rendering index. In this study, the results obtained highly indicates that SCMSO: Eu2+ is potentially blue-emitting phosphor for application in white LEDs.

To facilitate the next generation of environmental material for white light emitting diodes, the discovery of natural luminesce is essential. In this study, we disclose a rare-earth free and yellow-emission phosphor, Phellodendron, which could be both excited by near ultraviolet light and blue light. The new yellow phosphor is obtained by extraction of Phellodendron chinense Schneid. The emission wavelength, full width at half maximum and CIE coordinates of extracted Phellodendron are 540 nm, 120 nm and ( 0.41, 0.55), respectively. The corresponding luminescent properties of Phellodendron are characterized by PL, PLE, reflection spectra, FITR and decay lifetime. Surprising thing is luminous intensity of Phellodendron phosphors excited at 380 nm was stronger than YAG:Ce phosphor by more than 139%. In addition, we firstly introduce the yellow phosphor in white LED fabrication by combining blue chip and Y3Al5O12:Ce3+ phosphor, to create warm white. For comparison, red-emission CaAlSiN3:Eu2+ phosphors are also introduced for LED package tests. The results demonstrate that Phellodendron is a potential candidate for white LED applications.

In this study, we proposed a cost-effective method for preparing graphene nano-flakes (GNFs) derived from carbon nanotubes (CNTs) via three steps (pressing, homogenization and sonication exfoliation processes). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), laser scattering, as well as ultraviolet-visible and photoluminescence (PL) measurements were carried out. The results indicated that the size of as-synthesized GNFs was approximately 40-50 nm. Furthermore, we also used first principles calculations to understand the transformation from CNTs to GNFs from the viewpoints of the edge formation energies of GNFs in different shapes and sizes. The corresponding photoluminescence measurements of GNFs were carried out in this work.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A color-tunable BaCa2MgSi2O8:1%Eu2+, 20%Mn2+ phosphor demonstrates CIE coordinates of (0.3384, 0.2176) and CRI of 82. The results indicate that the as-synthesized phosphor could be a single-phased and white-emitting phosphor for use in UV LEDs.

A series of new alkaline-earth metal diphosphonate frameworks were successfully synthesized under solvothermal reaction condition (160 °C, 3 d) using 1-hydroxyethylidene-1,1-diphosphonic acid (CH3C(OH)(H2PO3)2, hedpH4) as a diphosphonate building block and Mg(II), Ca(II), Sr(II), or Ba(II) ions as alkaline-earth metal ion centers in water, dimethylformamide, and/or EtOH media. These diphosphonate frameworks, (H2NMe2)4[Mg(hedpH2)3]·3H2O (1), (H2NMe2)2[Ca(hedpH2)2] (2), (H2NMe2)2[Sr3(hedpH2)4(H2O)2] (3), and [Ba3(hedpH2)3]·H2O (4) exhibited interesting structural topologies (zero-, one-, two-, and three-dimensional (0D, 1D, 2D, and 3D, respectively)), which are mainly depending on the metal ions and the solvents used in the synthesis. The single-crystal analysis of these newly synthesized compounds revealed that 1 was a 0D molecule, 2 has 1D chains, 3 was a 3D molecule, and 4 has 2D layers. All compounds were further characterized using thermogravimetric analysis, solid-state (31)P NMR, powder X-ray diffraction analysis, UV-vis spectra, and infrared spectroscopy. In addition, Eu(III)- and Tb(III)-doped compounds of 1-4, namely, (H2NMe2)4[Ln(x)Mg(1-x)(hedpH2)2(hedpH(2-x))]·3H2O (1Ln), (H2NMe2)2[Ln(x)Ca(1-x)(hedpH2)(hedpH(2-x))] (2Ln), (H2NMe2)2[Ln(x)Sr(3-x)(hedpH2)3(hedpH(2-x))(H2O)2] (3Ln), and [Ln(x)Ba(3-x)(hedpH2)2(hedpH(2-x))]·H2O (4Ln) (where Ln = Eu, Tb), were synthesized, and their photoluminescence properties were studied. The quantum yield of 1Eu-4Eu was measured with reference to commercial red phosphor, Y2O2S:Eu(3+) (YE), and the quantum yield of terbium-doped compounds 1Tb-4Tb was measured with reference to commercial green-emitting phosphor CeMgAl10O17:Tb(3+). Interestingly, the compound 2Eu showed very high quantum yield of 92.2%, which is better than that of the reference commercial red phosphor, YE (90.8%).

A high intense blue-emitting phosphor CaScAlSiO6:Eu2+ (CSAS:Eu2+) peaking at 430-460 nm was synthesized by solid state reactions. The luminescence properties of CSAS:Eu2+ phosphors as well as thermal quenching and the fabrication of white-light-emitting diodes (W-LEDs) were firstly investigated. The optimal doping concentration of Eu2+ is 2 mol% and the critical distance for energy transfer is determined to be 19.49 angstrom. By utilizing a mixture of blue-emitting CSAS:Eu2+, green-emitting SrSi2O2N2:Eu2+ and red-emitting CaAlSiN3:Eu2+ phosphors as light converters, an intense white GaN-based n-UV-LED (370 nm) was fabricated to exhibit good color-rendering index R-a of as high as 87.98 at correlated color temperature of 5537 K and CIE coordinates of (0.33, 0.42). Based on the results, we are currently evaluating the potential application of CSAS:Eu2+ as a blue-emitting near-UV convertible phosphor.

Nitrogen-doped YAG : Ce3+ phosphors have been firstly studied by using hexamethylenetetramine (HMT) as a nitrogen source by a solid state reaction. The optimal content of HMT is by introducing 50 wt.% with precursors of Y2O3, Al2O3 and CeO2 under annealing at 1450 degrees C for 8 hours. The XRD data indicate that the lattice constants increase with the content of HMT. SEM morphologies demonstrate that after nitrogen doping, the surface and particle size of YAG become smoother and larger than un-treated one. The PL intensity of YAG : Ce after HMT treatment gives a incensement in range of 3.46% similar to 9.87%. The luminous efficacy of as-synthesized YAG : Ce phosphor + Blue chip was dramatically enhanced by 40%. Using the doped samples, the white LED luminous efficiency obtained 78.4 lm/W and was successfully obtained with the combination of blue LED chip, thus improving the performance of the LED. The enhancement in luminesce was resulted from the modification of its surface morphology, crystallinity and grain size.

Bi 3+ /Eu 3+ co-activated Sr 3 Lu 2 (BO 3 ) 4 was successfully synthesized via a solid state reaction. The optimal concentration of Bi 3+ ,Eu 3+ and Bi 3+ /Eu 3+ are 1 mol%, 60 mol% and 1 mol%/20 mol%, respectively. The emission spectra of Sr 3 Lu 2 (BO 3 ) 4 :Bi 3+ , Eu 3+ gives three peaks located at 405 nm, 489 nm which were attributed to Bi 3+ S 6 (blue) and C 2 (green) site symmetry, respectively and 610 nm which was ascribed to Eu 3+ ( 5 D 0 → 7 F 2 ) transition. The emission intensity of Bi 3+ decreases with increasing Eu 3+ content which indicates that a efficient energy transfer occurred in the Sr 3 Lu 2 (BO 3 ) 4 host. The relative intensity of Sr 3 Lu 1.79 (BO 3 ) 4 :0.01Bi 3+ ,0.20Eu 3+ excited at 327 nm and 370 nm was remarkably enhanced by 201% and 265%, respectively, via the energy transfer from Bi 3+ to Eu 3+ . The results indicate that Sr 3 Lu 2 (BO 3 ) 4 :Bi 3+ , Eu 3+ is a potential novel red-emitting phosphor for UV LED applications.

A color-tunable NaCaY(PO₄)₂:Eu²⁺,Mn²⁺, was synthesized by a solid state reaction. NaCaY(PO₄)₂ crystallizes in the hexagonal structure system with space group of P6₂22 and Z = 1. The NaCaY(PO₄)₂:Eu²⁺ exhibits blue-greenish emission and broad excitation bands corresponding to the allowed f→d electronic transition of Eu²⁺. In addition, via the design of efficient energy transfer from Eu²⁺ to Mn²⁺, a high quality of white-emitting light could be generated in the optimized composition of NaCaY(PO₄)₂:1%Eu²⁺, 0.5%Mn²⁺ with CIE coordinates of (0.3389,0.3531) and CRI of 82, which is superior than that of blue chip and YAG phosphors. The results indicate that as-synthesized NaCaY(PO₄)₂:Eu²⁺,Mn²⁺ phosphors exhibits the potential to be an n-UV convertible phosphor.

Novel green-emitting phosphor – Li6Lu(BO3)3:Ce3+, Tb3+ phosphors exhibit intense green emission via the energy transfer from Ce3+ to Tb3+. The data demonstrated that the phosphor is a promising green-emitting phosphor for UV LED applications.