ORCID Profile
0000-0002-2840-1880
Current Organisation
Southern University of Science and Technology
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Publisher: IOP Publishing
Date: 17-11-1999
Publisher: IOP Publishing
Date: 02-04-2012
DOI: 10.1088/0022-3727/45/16/165103
Abstract: We have fabricated a dye-sensitized solar cell (DSSC) with a pair of carbon-based electrodes using a transparent, conductive carbon nanotubes (CNTs) film modified with ultra-thin titanium-sub-oxide (TiO x ) as the working electrode and a bilayer of conductive CNTs and carbon black as the counter electrode. Without TiO x modification, the DSSC is almost nonfunctional whereas the power conversion efficiency (PCE) increases significantly when the working electrode is modified with TiO x . The performance of the cell could be further improved when the carbon black film was added on the counter electrode. The improved efficiency can be attributed to the inhibition of the mass recombination at the working electrode/electrolyte interface by TiO x and the acceleration of the electron transfer kinetics at the counter electrode by carbon black. The DSSC with a pair of carbon-based electrodes gives the PCE of 1.37%.
Publisher: IEEE
Date: 2008
Publisher: AIP Publishing
Date: 13-08-2007
DOI: 10.1063/1.2772668
Abstract: Surface modification of ZnO nanocombs was performed through a Ti plasma immersion ion implantation (PIII) with low bias voltages ranging from 0to5kV to quench surface-originated exciton emission. The ion energy dependent surface modification on ZnO was investigated using transmission electron microscopy and temperature-dependent photoluminescence (PL). The surface exciton (SX) was clearly identified for the as-grown s le at 4.5K, and complete quenching was observed for s le treated with 5kV PIII due to surface state passivation. The SX related surface states were located within 5nm in depth from the surface corresponding to the implantation depth of 5kV PIII. Room-temperature PL enhancement of these surface-modified ZnO nanocombs was observed and discussed. The results show that PIII can become a viable technique for nanostructure surface passivation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TA01764B
Abstract: We demonstrate metal-oxide-free solution-processed inverted PSCs using sulfur-containing azaacene TDTP as the ETL with a PCE of ∼18.2%.
Publisher: Wiley
Date: 14-09-2016
Publisher: World Scientific Pub Co Pte Lt
Date: 20-01-2002
DOI: 10.1142/S0217979202009470
Abstract: It has been elegantly accepted that oxygen adsorption onto the Cu (110) surface induces an expansion of the first layer-spacing and a contraction of the second in addition to the alternative Cu [001] row that is either missing or forming the O-Cu-O row of high protrusions. However, it needs yet to clarify the vertical position of the oxygen and the hard-sphere models of added-, missing- and buckled-row. Here we justify that all the structures determined and all the models developed so far are correct in the sense of numerical solutions and phenomenological descriptions. A tetrahedral bond configuration of sp-orbital hybridization developed recently, however, may serve as a criterion to identify the physical solution that could account consistently for the observations using scanning tunneling microscopy/spectroscopy (STM/S), X-ray diffraction (XRD), and ultraviolet photoelectron spectroscopy (UPS).
Publisher: Elsevier BV
Date: 11-2017
Publisher: IOP Publishing
Date: 17-07-2001
Publisher: American Chemical Society (ACS)
Date: 05-1991
DOI: 10.1021/JO00011A060
Publisher: Elsevier BV
Date: 07-2009
Publisher: IOP Publishing
Date: 30-07-2003
Publisher: Elsevier BV
Date: 2006
Publisher: Elsevier BV
Date: 05-2005
Publisher: Wiley
Date: 26-04-2016
Publisher: American Chemical Society (ACS)
Date: 04-10-2011
DOI: 10.1021/CG2007149
Publisher: Elsevier BV
Date: 02-2017
Publisher: IOP Publishing
Date: 28-10-2014
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2011
Publisher: AIP Publishing
Date: 20-07-2009
DOI: 10.1063/1.3186046
Abstract: In this letter, Si thin film (800 nm thick) with nanopillar array decorated surface is studied via simulation for its solar energy absorption characteristics. It is found that the light absorption is significantly enhanced due to the adding of the Si nanopillar (SiNP) array to the Si thin film. The absorption characteristics of the SiNP structure would be approximately optimum (especially at ∼2.5 eV, the high energy density region in the solar spectrum) when the periodicity of SiNP array is set as ∼500 nm, which can be explained when comparing the incident light wavelength with the periodicity of SiNP array.
Publisher: AIP Publishing
Date: 11-07-2011
DOI: 10.1063/1.3610488
Abstract: Transparent and conductive carbon-based materials are promising for window electrodes in solid-state optoelectronic devices. However, the catalytic activity to redox reaction limits their application as a working electrode in a liquid-type dye-sensitized solar cell (DSSC). In this letter, we propose and demonstrate a transparent carbon nanotubes (CNTs) film as the working electrode in a DSSC containing iodide/triiodide redox couples. This implementation is realized by inhibiting the charge-transfer kinetics at CNT/redox solution interface with an aid of thin titanium oxide film that facilitates the unidirectional flow of electrons in the cell without sacrificing the electrical and optical properties of CNT.
Publisher: Wiley
Date: 27-04-2007
Publisher: IOP Publishing
Date: 11-01-2011
DOI: 10.1088/0022-3727/44/4/045102
Abstract: We report on top-illuminated, fluorine tin oxide/indium tin oxide-free (FTO/ITO-free), dye-sensitized solar cells (DSCs) using room-temperature-processed ZnO layers on metal substrates as the working electrodes and Pt-coated Ga-doped ZnO layers (GZO) as the counter electrodes. These top-illuminated DSCs with GZO render comparable efficiency to those employing commercial FTO counter electrodes. Despite a lower current density, the top-illuminated DSCs result in a higher fill factor than conventional DSCs due to a low ohmic loss at the electrode/semiconductor interface. The effect of metal substrate on the performance of the resulting top-illuminated DSCs is also studied by employing various metals with different work functions. Ti is shown to be a suitable metal to be used as the working electrode in the top-illuminated device architecture owing to its low ohmic loss at the electrode/semiconductor interface, minimum catalytic activity on redox reactions and high resistance to corrosion by liquid electrolytes.
Publisher: Springer Science and Business Media LLC
Date: 23-09-2014
DOI: 10.1038/NCOMMS5921
Abstract: Electrochromic smart windows are regarded as a good choice for green buildings. However, conventional devices need external biases to operate, which causes additional energy consumption. Here we report a self-powered electrochromic window, which can be used as a self-rechargeable battery. We use aluminium to reduce Prussian blue (PB, blue in colour) to Prussian white (PW, colourless) in potassium chloride electrolyte, realizing a device capable of self-bleaching. Interestingly, the device can be self-recovered (gaining blue appearance again) by simply disconnecting the aluminium and PB electrodes, which is due to the spontaneous oxidation of PW to PB by the dissolved oxygen in aqueous solution. The self-operated bleaching and colouration suggest another important function of the device: a self-rechargeable transparent battery. Thus the PB/aluminium device we report here is bifunctional, that is, it is a self-powered electrochromic window as well as a self-rechargeable transparent battery.
Publisher: AIP Publishing
Date: 02-11-2012
DOI: 10.1063/1.4766279
Abstract: We report on the tunable photovoltaic effect of self-doped single-crystal SrTiO3 (STO), a prototypical perovskite-structured complex oxide, and evaluate its performance in Schottky junction solar cells. The photovaltaic characteristics of vacuum-reduced STO single crystals are dictated by a thin surface layer with electrons donated by oxygen vacancies. Under UV illumination, a photovoltage of 1.1 V is observed in the as-received STO single crystal, while the s le reduced at 750 °C presents the highest incident photon to carrier conversion efficiency. Furthermore, in the STO/Pt Schottky junction, a power conversion efficiency of 0.88% was achieved under standard AM 1.5 illumination at room temperature. This work establishes STO as a high-mobility photovoltaic semiconductor with potential of integration in self-powered oxide electronics.
Publisher: AIP Publishing
Date: 15-10-2009
DOI: 10.1063/1.3251370
Abstract: We investigate the photoconductivity properties of ZnO thin films prepared by pulsed laser deposition with and without metals (Au or Pt) on the surface. The covering of nanostructured metals can largely enhance the photocurrent. Meanwhile, the dark currents have been increased significantly due to the increase in carrier concentration and mobility near the surface of ZnO thin film. Although plasmonic effect was observed by the photoluminescence enhancement, the main mechanism of the increase in the dark current and photoresponsivity for ZnO photoconductors has been interpreted by surface states, interface states, and persistent photoconductivity.
Publisher: AIP Publishing
Date: 15-02-2002
DOI: 10.1063/1.1434546
Abstract: An approach improving diamond–metal adhesion has been developed based on modeling predictions and experimental verifications on the interfacial stresses modified by catalytic reaction. It is found that N-plasma irradiating onto Ti and tungsten-carbide substrates generates tensile surface stresses while C-plasma irradiation creates strongly compressive stress at the surfaces, both of which deteriorate the diamond–metal adhesion. It is also found that surface oxidation prevents diamond nucleation. Therefore, we applied a graded TiCN interlayer with carefully adjusting the ratio of C and N in the gas mixture to neutralize the interfacial stress and, hence, we have improved the diamond–metal adhesion substantially.
Publisher: AIP Publishing
Date: 09-2001
DOI: 10.1063/1.1390305
Abstract: It is shown that bond contraction and nonbonding lone-pair interaction dominate at nitride surfaces. The maximum elastic recovery of a nitride surface was found to be 100% under a relatively lower nanoindentation load (& .0 mN) and the hardness of the surface was found to be 100% higher than the bulk value. It is interpreted that the spontaneous bond contraction, estimated at 12%–14%, strengthens the binding energy and hence the hardness and Young’s modulus at the surface. The lone-pair weak interaction claims the responsibility for (i) the high elastic recovery, (ii) the lower Raman frequencies of vibration, and (iii) the existence of critical loads for slide friction or lone-pair broken.
Publisher: AIP Publishing
Date: 20-08-2001
DOI: 10.1063/1.1394946
Abstract: A single band of photoluminescence (PL) has been detected at room temperature from the Pb(ZrxTi1−x)O3 (x=0–1.0) surface. The intense and stable PL band covers 475±50 nm (or 2.67±0.25 eV) wavelengths and the corresponding photoexcitation (PE) band is in the range of 305±45 nm. It is found that changing the x value causes a negligible shift of the PL and PE peaks, and the light emission is subject to the Pb presence. The minimal lifetime of the excited photons was found to be 0.03 ms at x=0.5 and the maximum lifetime of 0.60 ms can be achieved by either decreasing or increasing the x values.
Publisher: Wiley
Date: 16-04-2013
Publisher: SPIE
Date: 24-10-2000
DOI: 10.1117/12.405426
Publisher: AIP Publishing
Date: 02-08-2005
DOI: 10.1063/1.2009831
Abstract: A comparative study of in situ postgrowth annealing of organic layers before metal cathode was conducted on tris-(8-hydroxyqunoline) aluminum (Alq3)-based organic light-emitting devices (OLEDs). The devices were fabricated in the same run with a standard device without annealing for comparison, with an identical structure of indium tin oxide (ITO)/copper phthalocyanine (CuPc) (10nm)∕N,N′-di(naphthalene-l-yl)-N,N′-diphenyl-benzidine (NPB) (90nm)∕Alq3(90nm)∕Mg:Ag(200nm)∕Ag(20nm). The annealing temperature used was 60, 80, and 100°C, respectively. It was found that, in situ postgrowth annealing improves the device performance, and annealing near the glass transition temperature of NPB (99.7°C), improves device performance drastically. Power efficiency and current efficiency increase significantly with the annealing temperature, except the current efficiency for device annealed at 100°C is slightly lower than that of the standard device. The voltage and current density for 100cd∕m2 luminance are 5.6V and 4.4mA∕cm2, respectively, for the device annealed at 100°C, in comparison to 9.2V and 4.3mA∕cm2, respectively, for the standard device, the power efficiency is much improved by more than 40%. The in situ postgrowth annealed organic layers were characterized by photoluminescence and Raman spectroscopy.
Publisher: IOP Publishing
Date: 27-04-2004
Publisher: Elsevier BV
Date: 07-2006
Publisher: Wiley
Date: 25-04-2013
Publisher: Optica Publishing Group
Date: 24-12-2009
DOI: 10.1364/OL.35.000040
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2011
Publisher: IOP Publishing
Date: 05-12-2001
Publisher: American Chemical Society (ACS)
Date: 27-08-2009
DOI: 10.1021/NN9006797
Abstract: We report a general thermal transformation approach to synthesize single-crystalline magnetic transition metal oxides nanotubes/nanorings including magnetite Fe(3)O(4), maghematite gamma-Fe(2)O(3), and ferrites MFe(2)O(4) (M = Co, Mn, Ni, Cu) using hematite alpha-Fe(2)O(3) nanotubes/nanorings template. While the straightforward reduction or reduction-oxides process was employed to produce Fe(3)O(4) and gamma-Fe(2)O(3), the alpha-Fe(2)O(3)/M(OH)(2) core/shell nanostructure was used as precursor to prepare MFe(2)O(4) nanotubes via MFe(2)O(4-x) (0 < x < 1) intermediate. The transformed ferrites nanocrystals retain the hollow structure and single-crystalline nature of the original templates. However, the crystallographic orientation-relationships of cubic spinel ferrites and trigonal hematite show strong correlation with their morpologies. The hollow-structured MFe(2)O(4) nanocrystals with tunable size, shape, and composition have exhibited unique magnetic properties. Moreover, they have been demonstrated as a highly effective peroxidase mimic catalysts for laboratory immunoassays or as a universal nanocapsules hybridized with luminescent QDs for magnetic separation and optical probe of lung cancer cells, suggesting that these biocompatible magnetic nanotubes/nanorings have great potential in biomedicine and biomagnetic applications.
Publisher: American Chemical Society (ACS)
Date: 27-02-2009
DOI: 10.1021/NN800808S
Abstract: We report the fabrication and characterization of ZnO nanowire memory devices using a ferroelectric Pb(Zr(0.3)Ti(0.7))O(3) (PZT) film as the gate dielectric and the charge storage medium. With a comparison to nanowire transistors based on SiO(2) gate oxide, the devices were evaluated in terms of their electric transport, retention, and endurance performance. Memory effects are observed as characterized by an eminent counterclockwise loop in I-V(g) curves, which is attributed to the switchable remnant polarization of PZT. The single-nanowire device exhibits a high (up to 10(3)) on/off ratio at zero gate voltage. Our results give a proof-of-principle demonstration of the memory application based on a combination of nanowires (as channels) and ferroelectric films (as gate oxide).
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2011
Publisher: AIP Publishing
Date: 10-2008
DOI: 10.1063/1.2981189
Abstract: Single-crystalline, transparent conducting ZnO nanowires were obtained simply by Ti plasma immersion ion implantation (PIII). Electrical transport characterizations demonstrate that the n-type conduction of ZnO nanowire could be tuned by appropriate Ti-PIII. When the energy of PIII is increased, the resistivity of ZnO decreases from 4×102 to 3.3×10−3 Ω cm, indicating a semiconductor-metal transition. The failure-current densities of the metallic ZnO could be up to 2.75×107 A/cm2. Therefore, this facile method may provide an inexpensive alternative to tin doped indium oxide as transparent conducting oxide materials.
Publisher: Springer Science and Business Media LLC
Date: 25-07-2012
DOI: 10.1038/SREP00533
No related grants have been discovered for Xiaowei Sun.