State Key Laboratory of Optoelectronic Materials and Technologies

Guangzhou, China

State Key Laboratory of Optoelectronic Materials and Technologies

Guangzhou, China

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Xie W.,Siyuan Laboratory | Su M.,Siyuan Laboratory | Zheng Z.,State Key Laboratory of Optoelectronic Materials and Technologies | Wang Y.,Siyuan Laboratory | And 10 more authors.
ACS Nano | Year: 2016

The hydrogenation process of the layered α-MoO3 crystal was investigated on a nanoscale. At low hydrogen concentration, the hydrogenation can lead to formation of HxMoO3 without breaking the MoO3 atomic flat surface. For hydrogenation with high hydrogen concentration, hydrogen atoms accumulated along the <101> direction on the MoO3, which induced the formation of oxygen vacancy line defects. The injected hydrogen atoms acted as electron donors to increase electrical conductivity of the MoO3. Near-field optical measurements indicated that both of the HxMoO3 and oxygen vacancies were responsible for the coloration of the hydrogenated MoO3, with the latter contributing dominantly. On the other hand, diffusion of hydrogen atoms from the surface into the body of the MoO3 will encounter a surface diffusion energy barrier, which was for the first time measured to be around 80 meV. The energy barrier also sets an upper limit for the amount of hydrogen atoms that can be bound locally inside the MoO3 via hydrogenation. We believe that our findings has provided a clear picture of the hydrogenation mechanisms in layered transition-metal oxides, which will be helpful for control of their optoelectronic properties via hydrogenation. © 2015 American Chemical Society.


He C.,State Key Laboratory of Optoelectronic Materials and Technologies | He C.,Sun Yat Sen University | Shen P.K.,State Key Laboratory of Optoelectronic Materials and Technologies | Shen P.K.,Sun Yat Sen University
Nano Energy | Year: 2014

We report a microwave-assisted method to synthesize truncated hexagonal pyramid (THP) tungsten carbide with 5nm in size on graphene sheets (WCTHP/G) for the first time. The high-resolution transmission electron microscope (HRTEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis confirm that the WCTHP nanoparticles are dominated by (011-0), (101-0) and (11-00) facets with a preferred orientation of [0001]. The Pt loaded WCTHP/G materials show high activity and extremely high stability in electrocatalysis. This method can be developed as a general strategy for synthesizing high surface area, nanostructured transition metal carbides (TMCs) and utilizing them as active and low-cost catalysts or catalyst supports in a broad range of sustainable energy technologies. © 2014 Elsevier Ltd.


Ke X.,State Key Laboratory of Optoelectronic Materials and Technologies | Deng L.-L.,State Key Laboratory of Optoelectronic Materials and Technologies | Shen P.-K.,State Key Laboratory of Optoelectronic Materials and Technologies | Cui G.-F.,Sun Yat Sen University
Chemical Research in Chinese Universities | Year: 2010

Pd was electrochemically deposited on gold-coated quartz crystals at nanogram-level. The coulombic efficiency and initial nucleation and growth mechanism of potentiostatic Pd deposition were investigated via in situ electrochemical quartz crystal microbalance(EQCM). The coulombic efficiencies are 84%, 93% and 95% for Pd deposition at 0.3, 0.2 and 0.1 V(vs. SCE), respectively. The results of chronoamperometric measurements show that the Pd deposition proceeded by an instantaneous nucleation(at 0.3 V) or progressive nucleation(at 0.2 and 0.1 V) in a three-dimensional(3D) growth mode. The catalytic activity of Pd-based electrocatalyst for ethanol oxidation was characterized in an alkaline solution. It was found that the highest mass activity for ethanol oxidation on Pd-based electrocatalyst is 1.8×10 4 A/(g Pd) deposited at 0.3 V for 5 s.


Zhong H.,State Key Laboratory of Optoelectronic Materials and Technologies | Yang G.,State Key Laboratory of Optoelectronic Materials and Technologies | Song H.,State Key Laboratory of Optoelectronic Materials and Technologies | Liao Q.,State Key Laboratory of Optoelectronic Materials and Technologies | And 5 more authors.
Journal of Physical Chemistry C | Year: 2012

New layered SnS 2 nanosheet arrays consisting of 1-5 atomic layers were synthesized directly on Sn foil as both the tin source and the metal current collector substrates by a simple biomolecule-assisted method. It is found that SnS 2 nanosheets synthesized have excellent photoelectric applications, such as on lithium ion batteries, and photocatalytic, field emission, and photoconductive properties. Cyclic voltammetry and discharge and charge behaviors of the atomic SnS 2 nanosheets were examined, and it shows that the average discharge capacity in 1050 mAh/g is much larger than the theoretical capacity at the 1C rate. The photocatalytic action driven by solar light is quite quick, and the degradation rate of RhB is 90%, only irradiated for 20 min when the content of SnS 2 nanosheets is 0.4 g/L. The response of the SnS 2 device to the incidence UV light is very fast and shows excellent photosensitivity and stability. In addition, field emission properties of SnS 2 nanosheets were also researched, and we found that the turn-on field for SnS 2 is 6.9 V/μm, which lowered ever reported values. The enhanced photoelectric properties are likely to originate in a graphene-like structure. Thus, graphene-like SnS 2 materials are promising candidates in the photoelectric field. © 2012 American Chemical Society.


Liu S.,State Key Laboratory of Optoelectronic Materials and Technologies | Liu S.,Zhanjiang Normal University | He P.,State Key Laboratory of Optoelectronic Materials and Technologies | Wang H.,State Key Laboratory of Optoelectronic Materials and Technologies | And 2 more authors.
Journal of Luminescence | Year: 2010

A dinuclear Eu (III) complex Eu 2(dbt) 3·4H 2O was synthesized, where H 2dbt was 2,8-bis(4′,4′,4′,-trifluoro-1′,3′-dioxobutyl)-dibenzothiophene. The complex emits the characteristic red luminescence of Eu 3+ ion due to the 5D 0→ 7F J(J=0-4) transitions under 395 nm-light excitation with a luminescent quantum efficiency of 17%. The complex is thermally stable up to 280 °C. It was found that the complex can be effectively excited by a 395 nm-emitting InGaN chip. Bright red light was obtained using the complex as light color-conversion material. © 2010 Elsevier B.V. All rights reserved.


PubMed | State Key Laboratory of Optoelectronic Materials and Technologies and Sun Yat Sen University
Type: | Journal: Scientific reports | Year: 2015

Nano-scale vacuum channel transistors possess merits of higher cutoff frequency and greater gain power as compared with the conventional solid-state transistors. The improvement in cathode reliability is one of the major challenges to obtain high performance vacuum channel transistors. We report the experimental findings and the physical insight into the field induced crystalline-to-amorphous phase transformation on the surface of the Si nano-cathode. The crystalline Si tip apex deformed to amorphous structure at a low macroscopic field (0.6~1.65 V/nm) with an ultra-low emission current (1~10 pA). First-principle calculation suggests that the strong electrostatic force exerting on the electrons in the surface lattices would take the account for the field-induced atomic migration that result in an amorphization. The arsenic-dopant in the Si surface lattice would increase the inner stress as well as the electron density, leading to a lower amorphization field. Highly reliable Si nano-cathodes were obtained by employing diamond like carbon coating to enhance the electron emission and thus decrease the surface charge accumulation. The findings are crucial for developing highly reliable Si-based nano-scale vacuum channel transistors and have the significance for future Si nano-electronic devices with narrow separation.


Li Z.L.,State Key Laboratory of Optoelectronic Materials and Technologies | Liu F.,State Key Laboratory of Optoelectronic Materials and Technologies | Xu N.S.,State Key Laboratory of Optoelectronic Materials and Technologies | Chen J.,State Key Laboratory of Optoelectronic Materials and Technologies | Deng S.Z.,State Key Laboratory of Optoelectronic Materials and Technologies
Journal of Crystal Growth | Year: 2010

Three-dimensional (3D) nanowire network is a potential building block for nanodevices. Films of 3D tungsten nanowire networks were found early, and the present study is to develop a technical procedure for achieving very high percentage of 3D tungsten nanowire networks in a film. We demonstrate that the content of 3D tungsten nanowire networks in a film, prepared by thermal vapor deposition, may be adjusted by controlling the temperature of substrate, and also that films of very high percentage of 3D tungsten nanowire networks may be prepared. It is found that all films exhibit stable field electron emission, but that the performance varies depending on content of 3D nanowire networks. © 2009 Elsevier B.V. All rights reserved.


Li D.,State Key Laboratory of Optoelectronic Materials and Technologies | She J.,State Key Laboratory of Optoelectronic Materials and Technologies | Xu S.,State Key Laboratory of Optoelectronic Materials and Technologies | Deng S.,State Key Laboratory of Optoelectronic Materials and Technologies
IEEE Transactions on Electron Devices | Year: 2013

The rational design and fabrication of zinc oxide (ZnO) nanowire (NW) lateral field electron emission device and the possible application as a display pixel structure are reported. In the device, the cathode and anode are ranked side-by-side on the same panel. The NW-clusters were controlled to locally grow on the edges of the electrodes with different tilted status, i.e., in angle range of 75° ~110°, 0°~110° and 0° ~57°, respectively. The devices with NWs at different tilt-angle showed distinct field electron emission properties. The device with 0° ~57° tilted NWs possess the best performance, i.e., an emission current of 9.3 μA (current density: 6.22 A/cm2 was obtained at a low cathode-anode (50 μm in separation) bias of 477 V. Stable cathodoluminescence was observed from the indium titanic oxide anode, suggests a possibility for display application. Mechanisms responsible for the enhanced field electron emission and the related device physics are proposed. Significantly, the low temperature (~80 °C) solution-phase growth of ZnO NWs enables the fabrication of the devices on flexible polyimide substrate, which has also been demonstrated here. This paper opens up possibilities on developing NW-based lateral field electron emission device for vacuum micro/nanoelectronics applications. © 1963-2012 IEEE.


Zhang X.,State Key Laboratory of Optoelectronic Materials and Technologies | Zhang J.,State Key Laboratory of Optoelectronic Materials and Technologies | Huang J.,State Key Laboratory of Optoelectronic Materials and Technologies | Tang X.,State Key Laboratory of Optoelectronic Materials and Technologies | Gong M.,State Key Laboratory of Optoelectronic Materials and Technologies
Journal of Luminescence | Year: 2010

A series of Eu2+-doped alkaline-earth apatites (alkaline-earth=Ca, Sr and Ba) were synthesized by a solid state reaction method with excess chlorides, and the effect of the used excess chlorides on the luminescent property of the synthesized products was discussed. Photoluminescence measurements showed that Eu2+-doped calcium apatite exhibited intensely blue wide-band emission peaking at 457 nm under near UV excitation among the Eu2+-doped Ca, Sr and Ba apatites. Blue and white LEDs were successfully fabricated by pre-coating the calcium apatite phosphors onto ∼395 nm-emitting InGaN chips. The CIE coordinates, color temperature, luminous efficacy and rendering index value of the fabricated white LED are (0.3432, 0.3234), 4969 K, 8 lm/W and 80, respectively. The results indicate that the Eu2+-activated calcium apatite phosphor is a promising candidate as a blue component for fabrication of near UV-based white LEDs. © 2009 Elsevier B.V. All rights reserved.


PubMed | State Key Laboratory of Optoelectronic Materials and Technologies
Type: Journal Article | Journal: Nanoscale | Year: 2015

Strongly coupled plasmonic nanostructures with sub-10 nm gaps can enable intense electric field enhancements which greatly benefit the various light-matter interactions. From the point view of practical applications, such nanostructures should be of low-cost, facile fabrication and processing, large-scale with high-yield of the ultrasmall gaps, and easy for integration with other functional components. However, nowadays techniques for reliable fabrication of these nanostructures usually involve complex, time-consuming, and expensive lithography procedures, which are limited either by their low-throughput or the small areas obtained. On the other hand, so far most of the studies on the sub-10 nm gap nanostructures mainly focused on the surface-enhanced Raman scattering and high-harmonic generations, while leaving other nonlinear optical properties unexplored. In this work, using a scalable process without any lithography procedures, we demonstrated a centimeter-scale ordered plasmonic nanorod array film (PNRAF) with well-defined sub-10 nm interparticle gaps as a versatile platform for strongly enhanced light-matter interactions. Specifically, we showed that due to its plasmon-induced localized electromagnetic field enhancements, the Au PNRAF could exhibit extraordinary intrinsic multi-photon avalanche luminescence (MAPL) and nonlinear saturable absorption (SA). Furthermore, the PNRAF can be easily integrated with semiconductor quantum dots (SQDs) as well as wide bandgap semiconductors to strongly enhance their fluorescence and photocurrent response, respectively. Our method can be easily generalized to nanorod array films consisting of other plasmonic metals and even semiconductor materials, which can have multiple functionalities derived from different materials. Overall, the findings in our study have offered a potential strategy for design and fabrication of nanostructures with ultrasmall gaps for future photonic and optoelectronic applications.

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