Co-reporter:Bing Tang, Hongxing Dong, Liaoxin Sun, Weihao Zheng, Qi Wang, Fangfang Sun, Xiongwei Jiang, Anlian Pan, and Long Zhang
ACS Nano November 28, 2017 Volume 11(Issue 11) pp:10681-10681
Publication Date(Web):October 9, 2017
DOI:10.1021/acsnano.7b04496
Single-mode laser is realized in a cesium lead halide perovskite submicron sphere at room temperature. All-inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) microspheres with tunable sizes (0.2–10 μm) are first fabricated by a dual-source chemical vapor deposition method. Due to smooth surface and regular geometry structure of microspheres, whispering gallery resonant modes make a single-mode laser realized in a submicron sphere. Surprisingly, a single-mode laser with a very narrow line width (∼0.09 nm) was achieved successfully in the CsPbX3 spherical cavity at low threshold (∼0.42 μJ cm–2) with a high cavity quality factor (∼6100), which are the best specifications of lasing modes in all natural nano/microcavities ever reported. By modulating the halide composition and sizes of the microspheres, the wavelength of a single-mode laser can be continuously tuned from red to violet (425–715 nm). This work illustrates that the well-controlled synthesis of metal cesium lead halide perovskite nano/microspheres may offer an alternative route to produce a widely tunable and greatly miniaturized single-mode laser.Keywords: cesium lead halide; microsphere; single-mode laser; wavelength tunable; whispering gallery mode;
Co-reporter:Ruili Zhang, Jinjun Ren, Xinqiang Yuan, Yun Cui, Lei Zhang, and Long Zhang
The Journal of Physical Chemistry C May 11, 2017 Volume 121(Issue 18) pp:10087-10087
Publication Date(Web):April 24, 2017
DOI:10.1021/acs.jpcc.7b01871
Glasses in the system xBi2O3–(100 – x)NaPO3 were prepared using transitional melting–quenching and characterized using solid state nuclear magnetic resonance (SSNMR), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FT-IR). The addition of Bi2O3 results in the depolymerization of the phosphorus chain and the formation of Q(n) (n = 0, 1, 2) phosphorus species, where n represents the number of P–O–P bonds that can be quantified using 31P magic angle spinning (MAS) NMR and constant-time double-quantum based dipolar recoupling effects nuclear alignment reduction (CT-DQ-DRENAR). The 23Na{31P}, 31P{23Na}, and XPS results consistently prove that both Na+ and Bi3+ ions are bounded by phosphorus tetrahedron [PO4]3–. Unlike other trivalent ions such as Ga3+ and Al3+, which connect with the phosphorus tetrahedron by corner-sharing, Bi3+ ions were first proved to share edge with the phosphorus tetrahedron by the analysis of 31P spectra, taking the charge balance and bond valence consideration into account. Such a difference in connectivity results in significant structural differences.
Co-reporter:Junxi Xie, Xiaojian Mao, Xiaokai Li, Benxue Jiang, Long Zhang
Ceramics International 2017 Volume 43(Issue 1) pp:40-44
Publication Date(Web):January 2017
DOI:10.1016/j.ceramint.2016.08.117
Y2O3–MgO nanocomposites are appropriate materials for hypersonic infrared windows and domes because of their low emissivity and improved mechanical properties. In this study, the synthesized Y2O3–MgO nanopowders are investigated to evaluate the influence of moisture absorption on the manufacturing process and properties of the resulting nanocomposites. It is shown that MgO plays a more significant role than Y2O3 in the moisture absorption of the composite nanopowders, and the absorbed moisture leads to a lowering IR transmittance of the final Y2O3–MgO nanocomposites. A higher calcination temperature improves the resistance to moisture absorption of Y2O3–MgO nanopowders, which is beneficial for IR transmittance of the final nanocomposites. In addition, increasing the sintering temperature to 1100 °C during spark plasma sintering (SPS) minimizes the influence of absorbed moisture on the IR transmittance of the final nanocomposites. In the water resistance test, the Y2O3–MgO nanocomposites demonstrate severely eroded surfaces and degraded IR transmittance after water erosion, suggesting the requirement for necessary water-proof treatments on such materials in practical applications.
Co-reporter:Yiguang Jiang, Benxue Jiang, Nan Jiang, Pande Zhang, ... Long Zhang
Journal of the European Ceramic Society 2017 Volume 37, Issue 15(Volume 37, Issue 15) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.jeurceramsoc.2017.05.054
An Nd3+-doped Sr9GdF21 (SGF) transparent pore-free polycrystalline ceramic is produced by the ceramization of single crystals. The average transmittance (TA) of the Nd3+-doped SGF ceramic (8-mm thick) is about 90.6% in the visible region and more than 92% in the near-IR region. The fracture toughness of the Nd3+-doped SGF ceramic is up to 1.28 MPa m1/2, which is significantly higher than that of similar types of ceramics. Gd3+ ions, acting as both buffer ions and pinning ions, effectively improve the optical and mechanical properties of the SGF ceramic, implying that the sample is a promising candidate for high-power lasers. Moreover, the SGF ceramic shows a high mid- and far-infrared (up to 9 μm) transmittance, low phonon energy, and high density (ρ = 4.8466 g/cm3), which pave the way for a wide range of applications such as infrared windows, mid- and far-infrared lasers, scintillators, and in photonics.
Co-reporter:Junxi Xie, Xiaojian Mao, Qiangqiang Zhu, Benxue Jiang, Long Zhang
Journal of the European Ceramic Society 2017 Volume 37, Issue 13(Volume 37, Issue 13) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.jeurceramsoc.2017.04.056
In this study, a citrate–nitrate combustion method was applied to synthesize composite Y2O3–MgO nanopowders. In order to optimize the synthesis condition to support sufficient combustion, the molar ratio of citric acid to nitrate (c/n molar ratio) used in the reaction mixtures was varied between 0.17 and 0.34. Nanopowders with an average particle size of 17 nm were achieved. The properties of these nanopowders indicated that the higher molar ratios decreased the unreacted organic components and increased the amount of carbide on the surface of the oxides, which helped to inhibit the formation of carbonate groups. The amount of carbonate groups was reduced with the increasing c/n molar ratio. Y2O3–MgO nanocomposites fabricated through hot-isostatic-pressing sintering showed a uniform distribution of Y2O3 and MgO grains, which had an average size of ∼180 nm. In addition, the absorption peaks at 1410 and 1511 cm−1 disappeared until the c/n molar ratio reached 0.28. A high average infrared transmittance of 83% in the range of 4000–1667 cm−1 (2.5–6 μm) was obtained in the nanocomposites.
Co-reporter:Shuilin Chen, Benxue Jiang, Qinghua Yang, Yiguang Jiang, ... Long Zhang
Journal of the European Ceramic Society 2017 Volume 37, Issue 10(Volume 37, Issue 10) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.jeurceramsoc.2017.03.057
A Ce-doped (Gd2Y)(Ga3Al2)O12 ceramic with good performance was fabricated by sintering in an oxygen atmosphere and hot isostatic pressing. The microstructure as well as the optical and scintillation characteristics of the ceramic was investigated. The ceramic exhibited a high transmittance of 78% in the range of 500–800 nm. The radioluminescence intensity of the ceramic reached up to 30 times that of a bismuth germinate single crystal, and the light yield within 750 ns shaping time was approximately 25800 photons/MeV under 137Cs γ-ray irradiation.
Co-reporter:Pande Zhang, Baoyan Chai, Benxue Jiang, Yiguang Jiang, ... Long Zhang
Journal of the European Ceramic Society 2017 Volume 37, Issue 6(Volume 37, Issue 6) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.jeurceramsoc.2017.01.023
Cr (0.2 at.%) and Nd (0.8 at.%) co-doped Lu3Al5O12 ceramics were fabricated with MgO as the sintering additive. The addition of a small amount of MgO can affect the grain boundary mobility and influence the number and location of micropores in ceramics during the sintering process. The results show that when the MgO content is 0.02 wt.%, high-transparency Cr,Nd:LuAG ceramics can be obtained by vacuum sintering at 1670 °C for 5 h followed by hot isostatic pressing (HIP) post-sintering at 1750 °C in an argon atmosphere (P = 200 MPa) for 5 h. The optimum in-line transmittance of the HIPed Cr,Nd:LuAG ceramics (3 mm thick) is 83.5% at a wavelength of 840 nm and 84.0% at 710 nm.
Co-reporter:Liangjie Pan, Benxue Jiang, Jintai Fan, Pande Zhang, Xiaojian Mao, Long Zhang
Optical Materials 2017 Volume 71(Volume 71) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.optmat.2016.06.020
•Ethanol-water solvent method was introduced to synthesize LuAG nano-powders.•LuAG powders with good dispersion were synthesized at high calcination temperature.•The specific surface area of LuAG powder was enhanced by adding the appropriate amount of ethanol.Aluminum Garnet (LuAG) precursors were co-precipitated by using ethanol–water as the precipitant solvent. The effect of different volume ratios of ethanol to water (R) on the preparation of pure-phase LuAG powders has been mainly studied. The evolution of phase, composition and micro-structure of the as-synthesized LuAG powders were characterized by TG/DTA, FTIR, XRD, BET, and SEM. The BET-equivalent diameter of LuAG nano particles increased with R. The ethanol–water solvent does not change the main composition of the LuAG precursors, but has great influence on the morphology of the final LuAG nano particles. Uniformly dispersed LuAG powders calcined at 1200 °C for 3 h with a particle size of approximately 120 nm were obtained by using ethanol–water solvent with proper R = 1. The mechanism of ethanol in the preparation process was discussed.
Co-reporter:Yiguang Jiang, Benxue Jiang, Pande Zhang, Shuilin Chen, Qijun Gan, Jintai Fan, Xiaojian Mao, Nan Jiang, Liangbi Su, Jiang Li, Haohai Yu, Long Zhang
Materials & Design 2017 Volume 113(Volume 113) pp:
Publication Date(Web):5 January 2017
DOI:10.1016/j.matdes.2016.10.026
•Ceramization of single crystals technique was developed.•Nd-doped Ca1 − xYxF2 + x transparent ceramic was prepared by ceramization of single crystal.•The sample exhibits high transmittance (T1053nm = 93.7%) and good mechanical properties (H = 3.4 GPa, K1c = 0.61 MPa m1/2).•The continuous wavelength laser operation was obtained with an output power of 35 mW by a fiber-coupled laser-diode.Transparent Nd-doped Ca1 − xYxF2 + x ceramics were obtained through the ceramization of single crystals, and the morphology, microstructural characteristics, optical properties, and laser performance of the ceramics were examined. The results indicated that the microstructure of the transparent Nd-doped Ca1 − xYxF2 + x ceramics was similar to that of traditional hot-pressed CaF2 ceramics. In addition, the transparent Nd-doped Ca1 − xYxF2 + x ceramics exhibited the same optical properties as the precursor single crystals. Furthermore, the ceramization of the precursor single crystals produced transparent Nd-doped Ca1 − xYxF2 + x ceramics with mechanical properties (microhardness H = 3.430 GPa, fracture toughness K1c = 0.61 MPa m1/2) that were superior to that of the Nd-doped Ca1 − xYxF2 + x single crystals. Continuous-wave laser operation with an output power of 35 mW was obtained through the application of a fiber-coupled laser diode with a central wavelength of approximately 808 nm. This suggests that the transparent Nd-doped Ca1 − xYxF2 + x ceramics fabricated in this study are promising candidates for diode-pumped solid-state lasers and laser amplifiers.Download high-res image (212KB)Download full-size image
Co-reporter:Pande Zhang, Benxue Jiang, Jintai Fan, Xiaojian Mao, Long Zhang
Optical Materials 2017 Volume 71(Volume 71) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.optmat.2016.06.026
•We prepared Cr-sensitized Nd:LuAG laser ceramics to improve the pumping efficiency of laser.•The effects of sintering additives in the valence states of Cr in Cr-sensitized Nd:LuAG were studied.•The effects of annealing atmosphere in the valence states of Cr in Cr-sensitized Nd:LuAG were studied.Cr and Nd co-doped laser ceramics, as the potential gain materials in inertial confinement fusion (ICF), have been widely investigated. And the study on valence states of chromium ions is important. The effects of sintering additives and annealing atmosphere on the valence state of chromium were studied in detail, and the results shown that the Cr valence states were demonstrated to be Cr2+ and Cr3+ ions in HIP-sintered Cr(0.2 at.%), Nd(0.8 at.%): LuAG laser ceramics. And the intensity of the near-infrared absorption band caused by Cr2+ ions was attenuated with the decreasing SiO2 concentration and increasing MgO amount. The near-infrared absorption could be eliminated by annealing in air. And the transformation of valence states of Cr ions in the Cr,Nd:LuAG ceramics were also confirmed by electron paramagnetic resonance and X-ray photoelectron spectroscopy.
Co-reporter:Hongxing Dong, Beier Zhou, Jingzhou Li, Jingxin Zhan, Long Zhang
Journal of Materiomics 2017 Volume 3, Issue 4(Volume 3, Issue 4) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.jmat.2017.06.001
•The latest development of ZnO optical cavity based microlasers has been systematically reviewed.•The synthesis of ZnO optical cavity with regular geometrical structure and optical analysis.•Fabry-Perot mode lasing and whispering gallery mode lasing with different morphologies.•New nano/micro fabrication technique and physical effects may derive the microlaser progress.Zinc oxide (ZnO) optical microcavity modulated UV lasers have been attracting a wide range of research interests. As one of the most important materials in developing high quality microcavity and efficient UV–visible optoelectronic devices due to its wide band gap (3.37 eV) and large exciton binding energy (∼60 meV). In this review, we summarized the latest development of ZnO optical cavity based microlasers, mainly including Fabry-Perot mode lasers and whispering gallery mode lasers. The synthesis and optical studies of ZnO optical microcavities with different morphologies were discussed in detail. Finally, we also consider that the research focus in the near future would include new nanotechnology and physical effects, such as nano/micro fabrication, surface plasmon enhancement, and quantum dot coupling, which may result in new and interesting physical phenomena.We review the current research on the development of ZnO optical microcavity based UV lasers, the synthesis of the optical cavities, theoretical analyses, and also present our viewpoint for the future focus in this research field.Download high-res image (300KB)Download full-size image
Co-reporter:Zhengyuan Bai, Jin He, Yan Wang, Kangpeng Wang, Rihong Li, Long Zhang
Journal of Luminescence 2017 Volume 192(Volume 192) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.jlumin.2017.07.043
In recent years, near-infrared (NIR) materials beyond the visible region (700–2500 nm) has emerged as a promising research field with applications toward telecommunications, photovoltaic, in-vivo imaging, etc. Such technologies will benefit greatly from the advantageous properties of NIR materials including broadband tunable emission, nonlinear optical properties, photostability, and simple chemical processing. Here, we report a facile approach to fabricate high stable and controllable luminescent NIR-emitting composites by confining PbS colloidal quantum dots (CQDs) in sol-gel nanoporous AlPO4 glasses. The transmission electron microscopy images combined with X-ray photoelectron spectra in different depth of PbS-AlPO4 composites (PACs) reveal the successful solidification of CQDs in nanoporous structure of glasses. The controllable luminescence of PACs is dependent on the size of PbS CQDs in solution and glass pore size. We show that the broadband (270 nm) and bimodal emission of PACs are tailored by designing different composited strategies on the incorporation of colloidal quantum dots in AlPO4 nanoporous glasses. Ultrafast nonlinear optical properties of PACs were investigated using an open-aperture Z-scan technique with 515 nm 340 fs pulses. The PACs exhibited obvious reverse saturable absorption in our experiments, with a nonlinear absorption coefficient of 7.17 × 10−2 cm/GW. Furthermore, the stability of PACs is investigated by emission spectra from a few days to 180 days. The results imply PACs has a better stability than other regular PbS-solid materials such as PbS-Al2O3 films and close-packed PbS-filter paper systems.
Co-reporter:Yangyang Xu, Xiaojian Mao, Jintai Fan, Xiaokai Li, ... Long Zhang
Ceramics International 2017 Volume 43, Issue 12(Volume 43, Issue 12) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.ceramint.2017.04.017
Y2O3 transparent ceramics were prepared from alcoholic slurries of Y2O3 nanopowders via a slip-casting method to avoid the hydrolysis issue. Polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG) and polyethylenimine (PEI) were used as dispersants to improve the rheological properties of the slurries. It was found that PEI is the most effective dispersant in ethanol. The adsorbed amount of PEI was evaluated by infrared absorption and rheology measurements. Y2O3 slurry with a solid loading of 20.8 vol% and a viscosity of <0.1 Pa s at the shear rate of 10 s−1 was obtained using 1.5 wt% PEI. The slurry yielded a homogeneous green body, and finally resulted in a high-quality Y2O3 ceramic with the in-line transmittance of 80% at 800 nm.
Co-reporter:Yiguang Jiang;Benxue Jiang;Nan Jiang;Pande Zhang;Shuilin Chen;Jintai Fan;Liangbi Su;Jiang Li
CrystEngComm (1999-Present) 2017 vol. 19(Issue 31) pp:4480-4484
Publication Date(Web):2017/08/07
DOI:10.1039/C7CE00735C
We systematically present the relationship between the optical properties and deformation of Nd,B-codoped MF2 (B = buffer ions; M = alkaline earth metal ions) transparent ceramics. Re-clustering of Nd3+ ions in ceramics was experimentally observed for the first time. The mechanism of re-clustering was studied.
Co-reporter:Ruili Zhang, Marcos de Oliveira, Zaiyang Wang, Roger Gomes Fernandes, Andrea S. S. de Camargo, Jinjun RenLong Zhang, Hellmut Eckert
The Journal of Physical Chemistry C 2017 Volume 121(Issue 1) pp:
Publication Date(Web):December 12, 2016
DOI:10.1021/acs.jpcc.6b11187
The structure of glasses in the systems (100 – x)B2O3–xPbF2 (x = 30, 40, and 50) and 50B2O3–(50 – x)PbO–xPbF2 (x = 5, 10, 15, 20, 25, 30, 35, 40, and 45) has been studied by solid state NMR and EPR spectroscopies. On the basis of 11B and 19F high resolution solid state NMR as well as on 11B/19F double resonance results, we develop a quantitative structural description on the atomic scale. 19F NMR results indicate a systematic dependence of the fluoride speciation on PbF2 content: At low x-values, F– ions are predominantly found on BO3/2F– units, whereas, at higher x-values, fluoride tends to be sequestrated into amorphous domains rich in PbF2. In addition, both pulsed EPR studies of Yb3+ doped glasses and photophysical studies of Eu3+ doped samples indicate a mixed fluoride/borate coordination of the rare-earth ions and the absence of nanophase segregation effects.
Co-reporter:Jinxin Zhan;Hongxing Dong;Shulin Sun;Xiaodong Ren;Jianjun Liu;Zhanghai Chen;Christoph Lienau
Advanced Optical Materials 2016 Volume 4( Issue 1) pp:126-134
Publication Date(Web):
DOI:10.1002/adom.201500442
A distinct “split and recoalescence” growth mechanism of tubular ZnO micro/nanostructures is observed for the first time. On the basis of experimental growth studies and first-principles calculations, it is proposed that H2/H2O vapor, added to the traditional carbothermal reduction process, changes the intrinsic surface energy of ZnO crystal, which affects the ZnO crystal growth mode and subsequently controls the geometry of ZnO micro/nanotubes. It is shown that these tubular ZnO micro/nanostructures exhibit regular hexagonal cross sections and smooth outer and inner surfaces. Optical studies of ZnO micro/nanotubes reveal characteristic coherent intensity modulations of their emission spectra which reflect the excitation of either whispering gallery modes or wave-guided modes. The specific type of mode can be selected by controlling the microtube geometry, specifically by its wall thickness to diameter ratio, as demonstrated both experimentally by photoluminescence spectroscopy, and theoretically by finite-element-method simulations.
Co-reporter:Yiguang Jiang, Pande Zhang, Tao Wei, Jintai Fan, Benxue Jiang, Xiaojian Mao and Long Zhang
RSC Advances 2016 vol. 6(Issue 60) pp:55366-55373
Publication Date(Web):03 Jun 2016
DOI:10.1039/C6RA10288C
Transparent glass ceramics containing CaF2 micron-sized crystals were prepared using a modified liquid-phase sintering route. The morphology and microstructural evolution of the CaF2 crystals before and after liquid-phase sintering were examined using X-ray diffraction, field-emission scanning electron microscopy and transmission microscopy. After sintering at 800 °C for 10 min, the CaF2 crystals were approximately 20 μm in size and were uniformly distributed throughout a precursor glass prepared using melt-quenching method. The glass ceramic containing CaF2 micron-sized crystals prepared using liquid-phase sintering achieved the highest in-line transmittance of 76% in the visible region and 92% in the near-IR region. High near-IR transmittance of glass ceramics was attributed to the matching of the refractive index of the precursor glass with that of CaF2 in the near-IR region. The luminescence properties and local environment of Eu3+ in the precursor glass and glass ceramic were investigated using photoluminescence spectra, photoluminescence lifetimes and phonon sideband spectroscopy, and the results determined that some of the Eu3+ ions in the precursor glass incorporate into CaF2 micron-sized crystals after sintering and enter C4v site symmetry.
Co-reporter:Tao Wei, Jingsong Wei, Kui Zhang, Qijun Zhou, Zhen Bai, Xin Liang, Qisong Li, Chenliang Ding, Yang Wang and Long Zhang
RSC Advances 2016 vol. 6(Issue 51) pp:45748-45752
Publication Date(Web):05 May 2016
DOI:10.1039/C5RA23627D
A crystalline telluride (Te) thin film was prepared by a radio frequency magnetron controlling sputtering method. The fabrication of arbitrary patterns was achieved successfully by our home-built direct laser writing system in the prepared Te thin film. To elucidate the mechanism of pattern formation, micro X-ray diffraction, micro Raman spectra and micro reflective spectra before and after exposure were analyzed in detail. The results reveal that the occurrence of arbitrary patterns may be ascribed to the decreased grain size in the Te thin film, which can further be confirmed by the results of AFM and section images of the Te thin film. It is a simple and cost-effective method for arbitrary pattern fabrication based on the reduction of grain size in the laser writing process.
Co-reporter:Ya-Pei Peng, Chuanfeng Wang, Xinqiang Yuan, Long Zhang
Journal of Luminescence 2016 Volume 172() pp:331-334
Publication Date(Web):April 2016
DOI:10.1016/j.jlumin.2015.12.017
An Er3+-doped oxyfluorogallate glass is investigated as a laser material with 2.7 µm emission. The 2.7 µm emission properties of the Er3+-doped oxyfluorogallate glasses are obtained using a 980 nm laser diode and their spontaneous transition probabilities and branching ratios are predicted using Judd–Ofelt theory. The maximum value of emission cross-section of Er3+ around 2.7 µm reached 1.32×10−20 cm2, which suggests a very promising application of oxyfluorogallate glass for efficient 2.7 µm solid-state laser system.
Co-reporter:Yiguang Jiang, Jintai Fan, Benxue Jiang, Xiaojian Mao, Chunlin Zhou, Long Zhang
Ceramics International 2016 Volume 42(Issue 8) pp:9571-9576
Publication Date(Web):June 2016
DOI:10.1016/j.ceramint.2016.03.039
Transparent Er3+-doped CaF2–silica glass ceramics were prepared by the direct physical introduction of Er3+ doped CaF2 nanocrystals into acid-catalyzed sol–gel silica glass. The physical methods of ball milling, ultrasonic baths, and stirring were investigated to disperse Er3+ doped CaF2 nanocrystals in the silica sols. The CaF2–silica sol mixture went through gelation and heat-treatment to form Er3+-doped CaF2–silica glass ceramics. The morphology of Er3+ doped CaF2 in silica glass did not change after heat-treatment at 600 °C for 10 h. The experimental results showed that Er3+ doped CaF2 in the glass ceramic prepared with the assistance of ball milling possesses the best dispersity and homogeneity. The highest in-line transmittance of the glass ceramic reached up to 85% in visible region. Glass ceramic exhibits efficient up-conversion emissions corresponding to the Er3+:4F9/2→4I15/2 transition and long lifetime of 4F9/2 level (1.73 ms) under 980 nm excitation.
Co-reporter:Xiaokai Li, Xiaojian Mao, Minghui Feng, Junxi Xie, Benxue Jiang, Long Zhang
Journal of the European Ceramic Society 2016 Volume 36(Issue 16) pp:4181-4184
Publication Date(Web):December 2016
DOI:10.1016/j.jeurceramsoc.2016.05.046
ZrO2 is considered an efficient sintering additive for transparent Y2O3 ceramics. However, the doping of tetravalent Zr4+ ions leads to a dark brown color of the ceramic after vacuum sintering. In this study, the optical properties of vacuum-sintered and air-annealed ceramics were characterized using transmittance spectra and a Commission International de l’Eclairage (CIE) diagram. The corresponding defects are investigated by electron paramagnetic resonance (EPR) spectra. The band gap of the vacuum-sintered samples is 2.72 eV, which is much smaller than that of the annealed sample. The results reveal that the VO+ (F+ center) and Zr3+ defects form transition energy levels near the top of the valence band and at the bottom of the conduction band, respectively. The color-related absorption is mainly attributed to the electronic transfer from the Zr3+ level to the conduction band and from the F+ center to the Zr3+ level.
Co-reporter:Xiaokai Li, Xiaojian Mao, Minghui Feng, Shen Qi, Benxue Jiang, Long Zhang
Journal of the European Ceramic Society 2016 Volume 36(Issue 10) pp:2549-2553
Publication Date(Web):August 2016
DOI:10.1016/j.jeurceramsoc.2016.03.024
Despite being the most common sintering additive of transparent Y2O3 ceramics, La2O3 still suffers from weight changes when used in manufacturing processes due to its absorption of moisture and carbon dioxide. In the present work, two stable precursors, La(OH)3 and La2O2CO3, were proposed for use as sintering additives for transparent Y2O3 ceramics; La2O3 powder was used for comparison. A series of experiments were conducted to investigate the influences of La2O3, La(OH)3 and La2O2CO3 on the optical properties of Y2O3 ceramics by comparing the properties of mixed powders, green bodies and their sintering behaviors. Samples using La(OH)3 or La2O2CO3 as sintering additives exhibited more favorable optical properties at similar sintering temperatures compared to those using La2O3. Transmittances close to the theoretical value at 4 μm were achieved for samples doped with La(OH)3 or La2O2CO3 sintered at 1800 °C.
Co-reporter:Shen Qi, Xiaojian Mao, Xiaokai Li, Minghui Feng, Benxue Jiang, Long Zhang
Materials Letters 2016 Volume 174() pp:167-170
Publication Date(Web):1 July 2016
DOI:10.1016/j.matlet.2016.03.121
•Wurtzite-structured aluminum nitride (AlN) hexagonal bipyramids were prepared.•The preferred growth direction of the AlN hexagonal bipyramids is [0001].•The AlN hexagonal bipyramids showed near-band edge emission at 512 nm.Wurtzite-structured aluminum nitride (AlN) hexagonal bipyramids were prepared via a carbothermal reduction nitridation method using alumina and carbon as the raw materials. The growth of the AlN hexagonal bipyramids is dominated by the vapor-solid (VS) mechanism with Fe2O3, SiO2 and Na2O acting as mineralizers under alternate gas pressures. The preferred growth direction of the AlN hexagonal bipyramids is [0001]. Photoluminescence spectra of the AlN hexagonal bipyramids showed near-band edge emission at 512 nm at room temperature. The AlN hexagonal bipyramids might be useful for optical micro-devices.
Co-reporter:Yan Wang, Jin He, Rihong Li, Siyuan Chen, Xinqiang Yuan, Long Zhang
Journal of Non-Crystalline Solids 2016 Volume 431() pp:88-92
Publication Date(Web):1 January 2016
DOI:10.1016/j.jnoncrysol.2015.04.021
•Sol–gel AlPO4 glass films as substrates for depositing PbS QDs•QD-AlPO4 films with tunable and bimodal photoluminescence in near infrared•Improved photostability of QD-AlPO4 films compared to naked QDs•Formation of close-packed QD solid systems evidenced by energy transferBroadly tunable and multi-emission PbS quantum dot (QD)-solid systems have drawn great attention to the applications of telecommunication, microelectronics and solar cells. Here, we propose a simple and practical method for creation of QD-systems in porous AlPO4 glass film matrix. Tunable and bimodal luminescent films in near infrared are achieved by a layer by layer assembly method with PbS QDs of different sizes. Atomic force microscopy and scanning electron microscopy reveal the successful deposition and homogeneous surface morphology of QD-AlPO4 glass films. Furthermore, as a result of adsorption and confinement from pores of AlPO4 substrate, the photostability of QD-AlPO4 glass films is dramatically improved. The red-shift of QD photoluminescence spectra after depositing onto the matrix and the energy transfer between QDs of different sizes indicate the formation of close-packed QD solid systems. This work extends the research in QD close-packed systems and has important implications for the applications of blended QDs in broadly tunable optical devices and telecommunication.
Co-reporter:Jin He, Pengfei Ma, Yan Wang, Rihong Li, Xinqiang Yuan, Long Zhang
Journal of Non-Crystalline Solids 2016 Volume 431() pp:130-134
Publication Date(Web):1 January 2016
DOI:10.1016/j.jnoncrysol.2015.04.030
Intense room-temperature terbium photoluminescence, with well-resolved optical bands corresponding to electron transitions 5D4 → 7Fj (j = 3–6) was observed from mesoporous AlPO4 glass after immersion in solutions of terbium nitrates and subsequent heat treatment. The modification of Tb ions for the AlPO4 network structure is revealed by XPS spectra. The PL mechanism of the formed nanocomposite is discussed through the effects of Tb concentration and excitation wavelength. Our results indicate that the mesoporous AlPO4 glass is a suitable matrix to incorporate rare earth ions as the light emitting material.
Co-reporter:Xiaojian Mao, Xiaokai Li, Minghui Feng, Jintai Fan, Benxue Jiang, Long Zhang
Journal of the European Ceramic Society 2015 Volume 35(Issue 11) pp:3137-3143
Publication Date(Web):October 2015
DOI:10.1016/j.jeurceramsoc.2015.04.034
Crack is a common phenomenon in ceramics, which often extends and breaks the ceramic bodies. In the present study, however, cracks formed a network inside some transparent La-doped yttria ceramics, while didn’t break the samples. The reason was studied by investigating the mixed La2O3 and Y2O3 powders using SEM, TG-TDA BET, and XRD. The crack network is attributed to the volume effects of La(OH)3 dehydration and solid state reaction of oxides, both proceed gradually instead of suddenly along with temperature increasing during heating procedure of sintering. Hence, the corresponding stresses made cracks inside La-doped yttria ceramics without broken the bodies. The cracks could be eliminated by increasing the powder calcination temperature to reduce the above volume effects.
Co-reporter:Hongxing Dong, Yang Liu, Shulin Sun, Zhanghai Chen and Long Zhang
Journal of Materials Chemistry A 2014 vol. 2(Issue 42) pp:8976-8982
Publication Date(Web):26 Aug 2014
DOI:10.1039/C4TC01223B
Optical resonant modes in microwire cavities with irregular hexagonal cross-section have been observed in the visible spectral range. Single-crystalline In2O3 microwire functioning as a promising semiconductor microcavity, was fabricated by a simple sublimation–oxidation–deposition strategy. By using a spatially resolved spectroscopic technique, the effects of the cross sectional geometry on optical modulations was carefully investigated. The experimental results fitted well with the plane wave interference model and finite element method simulations. Our results demonstrate that the In2O3 microwire optical resonator offers another practical example for the study of fundamental physics in the field of cavity optics, and may be helpful for the development of miniature cavity-based optoelectronic devices.
Co-reporter:Yang Liu;Hongxing Dong;Jian Lu;Jingxin Zhan;Jingzhou Li;Zhanghai Chen
Advanced Optical Materials 2014 Volume 2( Issue 11) pp:1090-1097
Publication Date(Web):
DOI:10.1002/adom.201400269
Single-crystalline Sb shallow-doped ZnO microwire wave-guided optical resonators are synthesized via a simple carbothermal reduction method. The formation of the ZnO wave-guided microcavities are investigated systematically, and the Sb film formed on the substrate is confirmed to be the critical factor in crystal growth. The optical signals of the annealed ZnO microcavities induced by the Sb related acceptor defects are clarified through a low-temperature spectrum detection technology. Excitation power and temperature dependence of UV lasing properties of the ZnO microcavities annealed in different atmospheres are studied. The results reveal that such high-quality Sb shallow-doped ZnO wave-guided microcavities have excellent optical responses and a strong light-field regulation capability, which would greatly promote the development of ZnO cavity-based photoelectronic devices.
Co-reporter:Hongxing Dong, Yang Liu, Jian Lu, Zhanghai Chen, Jun Wang and Long Zhang
Journal of Materials Chemistry A 2013 vol. 1(Issue 2) pp:202-206
Publication Date(Web):01 Oct 2012
DOI:10.1039/C2TC00070A
High quality tower-like ZnO microrods with hexagonal cross-sections were fabricated by a simple reduction–oxidation process. By using the spatially resolved spectroscopic technique, the stable UV lasing was directly observed and further investigated systematically. Our results demonstrated that such tower-like microrods can function as novel cavity based microlasers, which could have potential applications in optoelectronics.
Co-reporter:Yang Liu, Hongxing Dong, Shulin Sun, Wenhui Liu, Jinxin Zhan, Zhanghai Chen, Jun Wang and Long Zhang
Nanoscale 2013 vol. 5(Issue 10) pp:4123-4128
Publication Date(Web):18 Mar 2013
DOI:10.1039/C3NR00700F
A novel ZnO microwire optical resonator with a parallelogram cross-section is fabricated, which can effectively control the light field in two dimensions. Wave-guided Fabry–Pérot modes with different polarizations are directly observed and further investigated systematically. Such a ZnO optical resonator offers another building block for the development of optoelectronic devices.
Co-reporter:Jinxin Zhan, Hongxing Dong, Yang Liu, Yinglei Wang, Zhanghai Chen and Long Zhang
CrystEngComm 2013 vol. 15(Issue 47) pp:10272-10277
Publication Date(Web):27 Sep 2013
DOI:10.1039/C3CE41754A
We demonstrate an easy, novel synthesis of nanosheet-based flower-like ZnO microspheres without any catalyst and template. The layered hydroxide zinc acetate Zn5(OH)8(CH3COO)2·2H2O (LHZA) nanostructures, one of important and efficient precursors to synthesize three dimensional (3D) ZnO hierarchical microstructures, are first fabricated in aqueous solution at room temperature. The detailed crystal structure and formation mechanism of the LHZA are also investigated. It is noteworthy that the initial ZnO seed layer is crucial to the growth of the final nano/microarchitectures. We found that the as-synthesized hierarchical ZnO microspheres obtained from the decomposition of LHZA showed excellent photocatalytic activity for the photodegradation of rhodamine 6G. This facile, efficient, and economical work provides a new route to simply and mildly synthesize ZnO 3D hierarchical microspheres, which may be adopted to prepare other metal oxide microstructures.
Co-reporter:Kangpeng Wang, Jun Wang, Jintai Fan, Mustafa Lotya, Arlene O’Neill, Daniel Fox, Yanyan Feng, Xiaoyan Zhang, Benxue Jiang, Quanzhong Zhao, Hongzhou Zhang, Jonathan N. Coleman, Long Zhang, and Werner Josef Blau
ACS Nano 2013 Volume 7(Issue 10) pp:9260
Publication Date(Web):October 3, 2013
DOI:10.1021/nn403886t
Employing high-yield production of layered materials by liquid-phase exfoliation, molybdenum disulfide (MoS2) dispersions with large populations of single and few layers were prepared. Electron microscopy verified the high quality of the two-dimensional MoS2 nanostructures. Atomic force microscopy analysis revealed that ∼39% of the MoS2 flakes had thicknesses of less than 5 nm. Linewidth and frequency difference of the E12g and A1g Raman modes confirmed the effective reduction of flake thicknesses from the bulk MoS2 to the dispersions. Ultrafast nonlinear optical (NLO) properties were investigated using an open-aperture Z-scan technique. All experiments were performed using 100 fs pulses at 800 nm from a mode-locked Ti:sapphire laser. The MoS2 nanosheets exhibited significant saturable absorption (SA) for the femtosecond pulses, resulting in the third-order NLO susceptibility Imχ(3) ∼ 10–15 esu, figure of merit ∼10–15 esu cm, and free-carrier absorption cross section ∼10–17 cm2. Induced free carrier density and the relaxation time were estimated to be ∼1016 cm–3 and ∼30 fs, respectively. At the same excitation condition, the MoS2 dispersions show better SA response than the graphene dispersions.Keywords: 2D nanomaterials; MoS2; nonlinear optics; saturable absorption; transition metal dichalcogenides; ultrafast; Z-scan
Co-reporter:Hongxing Dong, Yang Liu, Guanghui Li, Xuewen Wang, Dan Xu, Zhanghai Chen, Ting Zhang, Jun Wang, Long Zhang
Sensors and Actuators B: Chemical 2013 178() pp: 302-309
Publication Date(Web):
DOI:10.1016/j.snb.2012.12.103
Co-reporter:Jin He ; Yan Wang ; Yang Liu ; Kangpeng Wang ; Rihong Li ; Jintai Fan ; Shiqing Xu
The Journal of Physical Chemistry C 2013 Volume 117(Issue 42) pp:21916-21922
Publication Date(Web):September 26, 2013
DOI:10.1021/jp407125e
Controllable simultaneous luminescent monolithic mesoporous AlPO4 glasses doped with Eu ions were fabricated by dipping into a Eu-containing solution, followed by sintering in air. Reduction of partial Eu3+ ions to Eu2+ were achieved after annealing Eu3+ ions in AlPO4 meso-structure, which resulted in simultaneous luminescence of Eu3+ (590 and 613 nm) and Eu2+ (450 nm). Controllable luminescence and color tunability from blue to red were liable to obtain, which were characterized by emission spectra and described by CIE diagram. A deliberate tailoring of luminescence of Eu2+ and Eu3+ is achieved by controlling the Eu ions concentrations, sintering temperatures, and excitation wavelengths. Reduction and oxidation reactions of Eu ions were investigated by controlling the sintering atmospheres. XRD pattern indicated the typical amorphous glassy phase without obvious phase-separation even in high concentration (0.1 M). The presence of Eu2+ ions, which were reduced from Eu3+ by hole–electron pairs and diffused into mesoporous structure, was revealed by XPS spectra.
Co-reporter:Hongxing Dong, Shulin Sun, Liaoxin Sun, Weihang Zhou, Lei Zhou, Xuechu Shen, Zhanghai Chen, Jun Wang and Long Zhang
Journal of Materials Chemistry A 2012 vol. 22(Issue 7) pp:3069-3074
Publication Date(Web):05 Jan 2012
DOI:10.1039/C1JM14330A
High quality ZnO multilayer hexagonal microplates and microtubes were fabricated via a simple carbothermal method without any catalysts, carrier gases, or low pressure. The formation of the ZnO microstructures with different morphologies was discussed in detail, and a possible thermodynamic viewpoint was proposed. Fabry–Pérot (FP) modes and UV lasing were directly observed using a spatially resolved spectroscopic technique. All the resonant modes observed experimentally were identified using finite-difference-time-domain simulations. Excitation power and temperature dependence of lasing properties of the ZnO microplate were further studied. Compared with the conventional one-dimensional nanowire/nanobelt FP cavities, such ZnO multilayer vertical-FP resonators have much less optical loss and excellent optical responses and may find potential applications in UV microlasers.
Co-reporter:Jun Wang, Kang-Shyang Liao, Daniel Früchtl, Ying Tian, Aisling Gilchrist, Nigel J. Alley, Enrico Andreoli, Brad Aitchison, Albert G. Nasibulin, Hugh J. Byrne, Esko I. Kauppinen, Long Zhang, Werner J. Blau, Seamus A. Curran
Materials Chemistry and Physics 2012 Volume 133(2–3) pp:992-997
Publication Date(Web):16 April 2012
DOI:10.1016/j.matchemphys.2012.02.003
A series of double-walled carbon nanotubes (DWNTs) and multi-walled nanotubes (MWNTs) functionalized with selected organic chromophores, fluorescein 5(6)-isothiocyanate (FITC), rhodamine B isothiocyanate (RITC) and fullerene (C60) were synthesized by covalently linking these electron-donor groups to the metallic nanotubes. These versatile carbon nanotube composites show remarkable nonlinear optical (NLO) performance, due to a merged effect of the complementary NLO characteristics of the moieties of the composites. The hybrids were characterized by UV–vis spectroscopy and Raman spectroscopy. Evidence suggests charge transfer species are formed between the chromophores and the nanotubes. The optical limiting performance of the DWNT, MWNT hybrids and carbon NanoBuds is found to be superior to that of single-walled nanotubes. Thermally induced light scattering from nanotube moieties is the primary mechanism dominating the NLO response. Reverse saturable absorption from fullerene moieties makes a significant contribution to the NLO response of fullerene containing hybrids and NanoBuds. Photoinduced charge transfer from the fullerenes or the organic chromophores (FITC and RITC) to nanotubes followed by absorption in the charge separated excited state may enhance the nonlinear absorption, thus an effective optical limiting response.Highlights► Double-walled and multi-walled nanotube hybrids linking the electron-donor groups. ► Charge transfer species are formed between the chromophores and the nanotubes. ► The optical limiting performances are superior to that of single-walled nanotubes. ► Thermally induced light scattering is primary mechanism for the optical limiting.
Co-reporter:Long Zhang
Journal of Non-Crystalline Solids 2011 Volume 357(11–13) pp:2207
Publication Date(Web):June 2011
DOI:10.1016/j.jnoncrysol.2011.03.040
Co-reporter:Yongfeng Ju;Yang Liao;Yinglong Sheng
Microfluidics and Nanofluidics 2011 Volume 11( Issue 1) pp:111-117
Publication Date(Web):2011 July
DOI:10.1007/s10404-011-0790-9
We report on fabrication of large-volume, square-shaped microfluidic chamber embedded in glass by scanning a tightly focused femtosecond laser beam inside a porous glass immersed in water. After the hollow structure is created in the porous glass substrate, the fabricated glass sample is post-annealed at 1,050°C during which it can be sintered into a compact glass. By the use of this technique, a 1 mm × 1 mm × 100 μm microchamber connected to four microfluidic channels is created inside the transparent glass substrate, showing that our technique allows for fabrication of not only thin channel structures with arbitrary lengths and configurations, but also hollow structures with infinitely large sizes.
Co-reporter:Rihong Li ; Youyu Fan ; Jiacheng Li ; Bin Tang ; Jintai Fan ; Jin He ; Jinjun Ren ; Jun Wang
The Journal of Physical Chemistry C 2011 Volume 115(Issue 18) pp:9176-9181
Publication Date(Web):April 18, 2011
DOI:10.1021/jp200596g
Transparent AlPO4 mesoporous glasses codoped with different amounts, as well as different molar ratios, of Rhodamine 6G (Rh6G) and Coumarin 102 (Cou102) were fabricated by a dipping method. Solidification of dyes in mesoporous AlPO4 glasses was probed by 27Al and 31P solid state NMR techniques. The interaction of dyes with the glassy AlPO4 network has been characterized by a new six-coordinated aluminum species (Al(6)) environment in 27Al MAS spectra, combined with advanced solid state NMR techniques probing 27Al−1H and 27Al−31P internuclear dipole couplings. Optical excitation and simultaneous dual-wavelength emission spectra of both series of samples show significant dependences on the Rh6G and Cou102 concentration and Cou102/Rh6G molar ratio. Efficient simultaneous dual-wavelength emission was observed at low dye concentration (<10−5 M), whereas at high dye concentration (>10−3 M), quenching of the fluorescence of Cou102 happened, but the fluorescence intensity was dependent on the Cou102/Rh6G molar ratio.
Co-reporter:Rihong Li, Long Zhang, Jinjun Ren, Thiago B. de Queiroz, Andrea S.S. de Camargo, Hellmut Eckert
Journal of Non-Crystalline Solids 2010 Volume 356(41–42) pp:2089-2096
Publication Date(Web):1 September 2010
DOI:10.1016/j.jnoncrysol.2010.07.058
Fluorescent AlPO4 xerogels doped with different amounts of Rhodamine 6G (Rh6G) laser dye were prepared by a one-step sol–gel process. In addition, mesoporous AlPO4 glasses obtained from undoped gels were loaded with different amounts of Rh6G by wet impregnation. Optical excitation and emission spectra of both series of samples show significant dependences on Rh6G concentration, revealing the influence of dye molecular aggregation. At comparable dye concentrations the aggregation effects are found to be significantly stronger in the gels than in the mesoporous glasses. This effect might be attributed to stronger interactions between the dye molecules and the glass matrix, resulting in more efficient dye dispersion in the latter. The interaction of Rh6G with the glassy AlPO4 network has been probed by 27Al and 31P solid-state NMR techniques. New five- and six-coordinated aluminum environments have been observed and characterized by advanced solid-state NMR techniques probing 27Al–1H and 27Al–31P internuclear dipole couplings. The fractional area of these new Al sites is correlated with the combined fractional area of two new Q(0)3Al and Q(0)2Al phosphate species observed in the 31P MAS NMR spectra. Based on this correlation as well as detailed composition dependent studies, we suggest that the new signals arise from the breakage of Al–O–P linkages associated with the insertion process.
Co-reporter:Rihong Li, Long Zhang, Andrea S.S. de Camargo, Hellmut Eckert
Journal of Non-Crystalline Solids 2010 Volume 356(44–49) pp:2569-2573
Publication Date(Web):1 October 2010
DOI:10.1016/j.jnoncrysol.2010.05.018
Rhodamine 6G (RH6G) laser dye-doped AlPO4 xerogel and glass were prepared via a simple sol–gel route by one-step process and two-step process, respectively. The aggregating behavior of dyes in xerogel and glass was studied by excitation and emission spectra. The results indicated the dye aggregates become significantly weak in AlPO4 glass than in xerogel, which might be attributed to the enhanced interactions between dye and AlPO4 network as well as the nano-scale separation of dye by the mesoporous structure of AlPO4 glass. The 27Al MAS NMR of AlPO4 glass confirms the interaction of RH6G with AlPO4 glass network. Incorporation of RH6G into AlPO4 glass converts Al(4) to Al(6) units, resulting in the increase of Al(6) concentration with the doped RH6G concentration.
Co-reporter:Bin Tang, Yi Yang, Youyu Fan, Long Zhang
Journal of Materials Science & Technology 2010 Volume 26(Issue 6) pp:558-563
Publication Date(Web):June 2010
DOI:10.1016/S1005-0302(10)60085-0
Co-reporter:Bin Tang, Chunfeng Wu, Jiacheng Li, Youyu Fan, Hefang Hu, Long Zhang
Journal of Non-Crystalline Solids 2009 Volume 355(37–42) pp:2006-2009
Publication Date(Web):1 October 2009
DOI:10.1016/j.jnoncrysol.2009.01.060
Windows for infrared sensors on missiles, aircraft and high energy laser systems must be of excellent spectral properties, high optical quality, large and durable enough to protect delicate sensors from harsh operating conditions. This paper describes work being done for IR window applications on heavy metal oxyfluoride (HMOF) glasses, which provide a combination of infrared transparency, strength, hardness, and environmental stability in a largely-sized formable material, and represents potential candidate materials for infrared windows.
Co-reporter:Long Zhang, Hellmut Eckert
Journal of Non-Crystalline Solids 2008 Volume 354(12–13) pp:1331-1337
Publication Date(Web):15 February 2008
DOI:10.1016/j.jnoncrysol.2006.10.089
Transparent and homogeneous aluminophosphate gels and glasses have been widely synthesized through an aqueous sol–gel route, extending significantly the glass-forming range compared to that accessible via the melt-cooling route. Different phosphorus precursors, sodium polyphosphate (NaPO3) and orthophosphate species (NaH2PO4 and/or H3PO4) were compared with regard to the macroscopic properties and the microscopic structure of the resultant gels and glasses as characterized by extensive high-resolution liquid- and solid-state NMR. Sodium polyphosphate solution results in a substantially wider composition range of homogenous gel formation than orthophosphate solutions, and the two routes produce significant structural differences in the sol and xerogel states. Nevertheless, the structures of the glasses obtained upon gel annealing above 400 °C are independent of the P-precursors used.
Co-reporter:Long Zhang, Carla C. de Araujo, Hellmut Eckert
Journal of Non-Crystalline Solids 2007 Volume 353(13–15) pp:1255-1260
Publication Date(Web):15 May 2007
DOI:10.1016/j.jnoncrysol.2006.10.065
A novel aluminum precursor, aluminum lactate (Al(lact)3), was used in the sol–gel synthesis of alumina-based systems. The peculiar chelation properties of aluminum lactate in aqueous solution make this precursor quite attractive for the sol–gel synthesis of alumina-containing materials. Based on the reaction of aluminum lactate with different precursors such as phosphorus, boron, fluorine and others, (Na2O–)Al2O3–P2O5, (Na2O–)Al2O3–B2O3, (Na2O–)Al2O3–B2O3–P2O5, (Na–)Al–P–O–F, amorphous gels and glasses were prepared. The local structures of glasses prepared by both sol–gel and melt-cooling methods were compared by using solid state NMR.
Co-reporter:Yiguang Jiang, Benxue Jiang, Xinqiang Yuan, Chuanfeng Wang, Jintai Fan, Qinghua Yang, Pande Zhang, Shuilin Chen, Ge Zhang, Xiaojian Mao, Long Zhang
Materials Letters (15 May 2017) Volume 195() pp:
Publication Date(Web):15 May 2017
DOI:10.1016/j.matlet.2017.02.067
•A Ce:YAG transparent glass ceramic was prepared by liquid-phase sintering route.•A novel precursor glass system was developed.•The sample exhibits a broad yellow emission band, long lifetime, good transparency, and low sintering temperature.A Ce:YAG transparent glass ceramic was prepared by liquid-phase sintering of a mixture of YAG-Al2O3-PbO-PbF2-B2O3 precursor glass with Ce:YAG nanocrystals. The microstructure, luminescence spectra and lifetime behaviors of the sample was investigated. The size of the YAG crystals inside the GC reached ∼20 µm. The average in-line transmittance (2-mm thick) of the GC was more than 56% in the visible region. The GC exhibited a broad yellow emission band, long lifetime (τ = 1.69 µs), good transparency, and low sintering temperature, implying that the composite is a promising candidate for high-power white light emitting diodes (WLEDs).
Co-reporter:Hongxing Dong, Yang Liu, Jian Lu, Zhanghai Chen, Jun Wang and Long Zhang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 2) pp:NaN206-206
Publication Date(Web):2012/10/01
DOI:10.1039/C2TC00070A
High quality tower-like ZnO microrods with hexagonal cross-sections were fabricated by a simple reduction–oxidation process. By using the spatially resolved spectroscopic technique, the stable UV lasing was directly observed and further investigated systematically. Our results demonstrated that such tower-like microrods can function as novel cavity based microlasers, which could have potential applications in optoelectronics.
Co-reporter:Hongxing Dong, Yang Liu, Shulin Sun, Zhanghai Chen and Long Zhang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 42) pp:NaN8982-8982
Publication Date(Web):2014/08/26
DOI:10.1039/C4TC01223B
Optical resonant modes in microwire cavities with irregular hexagonal cross-section have been observed in the visible spectral range. Single-crystalline In2O3 microwire functioning as a promising semiconductor microcavity, was fabricated by a simple sublimation–oxidation–deposition strategy. By using a spatially resolved spectroscopic technique, the effects of the cross sectional geometry on optical modulations was carefully investigated. The experimental results fitted well with the plane wave interference model and finite element method simulations. Our results demonstrate that the In2O3 microwire optical resonator offers another practical example for the study of fundamental physics in the field of cavity optics, and may be helpful for the development of miniature cavity-based optoelectronic devices.
Co-reporter:Hongxing Dong, Shulin Sun, Liaoxin Sun, Weihang Zhou, Lei Zhou, Xuechu Shen, Zhanghai Chen, Jun Wang and Long Zhang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 7) pp:NaN3074-3074
Publication Date(Web):2012/01/05
DOI:10.1039/C1JM14330A
High quality ZnO multilayer hexagonal microplates and microtubes were fabricated via a simple carbothermal method without any catalysts, carrier gases, or low pressure. The formation of the ZnO microstructures with different morphologies was discussed in detail, and a possible thermodynamic viewpoint was proposed. Fabry–Pérot (FP) modes and UV lasing were directly observed using a spatially resolved spectroscopic technique. All the resonant modes observed experimentally were identified using finite-difference-time-domain simulations. Excitation power and temperature dependence of lasing properties of the ZnO microplate were further studied. Compared with the conventional one-dimensional nanowire/nanobelt FP cavities, such ZnO multilayer vertical-FP resonators have much less optical loss and excellent optical responses and may find potential applications in UV microlasers.
