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- 2018
- Display Metrology
- dSiPM
- Quanta Image Sensor
- CMOS
- QIS
- Complementary Metal Oxide Semiconductor
- Digital Silicon Photo-Multiplier
- Single Photon Avalanche Diode
- SPAD
- Optoelectronic Information Science and Engineering
- The University of Edinburgh
- STMicroelectronics Imaging Division
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In-Situ covalent synthesis of gold nanorods on GO surface as ultrasensitive Raman probe
摘要： In this paper, using thiolated graphene oxide (GO‐O‐SH) as substrate, gold nanorods (AuNRs) covalently linked to the GO surface by in‐situ seed growth method were first reported. The as‐prepared composites were characterized by UV–vis spectrum, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT‐IR). Experimental results indicated that the introduction of short flexible organic chain between GO and AuNRs contributed to the homogenous synthesis of gold rods, and uniform gold nanorods with aspect ratio within 3~8 were covalently linked to the surface of GO with high stability and yield. The strategy represented an outstanding improvement in comparison to the traditional route for fabricating the two GO@AuNRs composites. Furthermore, based on coupling of nanomaterials, the composites could act as high sensitive Raman probe with limit of detection (LOD) reaching 1 × 10?12 M.
关键词： covalent synthesis,Raman probe,graphene oxide (GO),gold nanorods
更新于2025-09-23 15:23:52
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Microwave plasma torch synthesis of Zn Al oxides as adsorbent and photocatalyst for organic compounds removal
摘要： Zn-Al based oxides were synthesized using a microwave plasma torch (MPT) in which the precursors were introduced into the reaction chamber either upstream or downstream of the inlet, respectively. Zn\Al layered doubled oxide (LDO) samples with a layer-by-layer structure obtained from the downstream path exhibited high adsorption capacity for anionic species, i.e., acid red 27 (AR27) and methyl orange (MO) dyes through hydrogen bonding and electrostatic interaction. The adsorption behavior follows a pseudo-second-order model and the Langmuir isotherm, suggesting that chemisorption of adsorbate on the adsorbent surface plays a significant role. Zn\Al oxide (ZAO) powders prepared from the upstream path show high crystallinity, enabling them to photocatalytically degrade methyl blue (MB) dye solution under UV and visible light irradiation. The crystallization mechanisms for ZAO and LDO prepared by the MPT method were also proposed in this study. In summary, the MPT process is a facile, rapid, scalable, and cost-effective method for synthesizing of Zn\Al based materials for many practical applications.
关键词： Photocatalyst,Zn-Al oxide,Adsorbent,Microwave Plasma Torch Synthesis
更新于2025-09-23 15:23:52
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Systematic investigations on the effect of prolong UV illumination on optoelectronic properties of ZnO honeycomb nanostructures
摘要： Herein, the effect of prolong UV illumination over ZnO optoelectronic characteristics has been investigated. The photoluminescence analysis has shown significant enhancement in deep level emission (DLE) after sample being exposed to UV radiations. The formation of photo-induced oxygen vacancies (VO) over the ZnO surface was found to be responsible for such noteworthy enhancement in DLE. The observed phenomenon was further utilized for controlled incorporation of VO in ZnO via UV illumination, towards obtaining optimal device performance. The UV treated photo-detector has shown significantly high photo-responsivity and photo-sensitivity in the deep UV region.
关键词： Zinc oxide,Honeycomb structure,Deep UV photodetector,XRD,Lattice defects
更新于2025-09-23 15:23:52
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Optoelectronic Properties of Zinc Oxide: A First-Principles Investigation Using the Tran-Blaha Modified Becke-Johnson Potential
摘要： In this work, density functional theory (DFT) is used to investigate the influence of semi-local exchange and correlation effects on the electronic and optical properties of zinc oxide. It is found that the inclusion of such effects using the Tran–Blaha modified Becke–Johnson potential yields an excellent description of the electronic structure of this material giving an energy band gap which is systematically larger than the one obtained with standard local functionals such as the generalized gradient approximation. The discrepancy between the experimental and theoretical band gaps is then significantly reduced. We also calculated the dielectric functions of ZnO and find a violet shift to the absorption edge which is in good agreement with experimental results.
关键词： zinc oxide,electronic structure,optical properties
更新于2025-09-23 15:23:52
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Interface properties of nonpolar LiAlO2/SrTiO3 heterostructures
摘要： Advances in creating metal oxide heterostructures have received a great deal of attention because novel properties like two-dimensional electron gas (2DEG), which was first found in LaAlO3/SrTiO3 interface, while does not exist in the bulk materials. To extend the study on 2DEG, we investigate the electronic property of interesting nonpolar/nonpolar LiAlO2/SrTiO3 heterostructure (also perovskite/nonperovskite oxide heterostructure), with and without oxygen vacancies by first-principles calculations. Two types of interfaces, SrO/LiAlO2 and TiO2/LiAlO2 interfaces, were modeled with the stable stacking configurations. Oxygen vacancies at LiAlO2/SrTiO3 interface induce the carriers in this system. there is no 2DEG behavior detected. Our results show that three-dimensional transport behavior occurs in the perovskite/non-perovskite oxide interface.
关键词： Metal oxide heterostructures,First-principles calculations,Oxygen vacancies,LiAlO2,SrTiO3
更新于2025-09-23 15:23:52
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UV Illumination-Enhanced Molecular Ammonia Detection Based On a Ternary-Reduced Graphene Oxide–Titanium Dioxide–Au Composite Film at Room Temperature
摘要： In this work, we report on UV illumination enhanced room-temperature trace NH3 detection based on ternary composites of reduced graphene oxide nanosheets (rGO), titanium dioxide nanoparticles (TiO2) and Au nanoparticles as the sensing layer, which is firstly reported by far. The effect of UV state as well as componential combination and content on the sensing behavior disclosed that, rGO nanosheets served as not only a template to attach TiO2 and Au, but an effective electron collector and transporter; TiO2 nanoparticles acted as a dual UV and NH3 sensitive material; Au nanoparticles could increase the sorption sites and promote charge separation of photoinduced electron-hole pairs. The as-prepared rGO/TiO2/Au sensors were endowed with a sensing response of 8.9% toward 2 ppm NH3, a sensitivity of 1.43×10-2/ppm within the investigated range, nice selectivity, robust operation repeatability and stability, which was fairly competitive in comparison with previous work. Meanwhile, the experimental results provided clear evidence of inspiring UV-enhanced gas detection catering for the future demand of low power-consumption and high sensitivity.
关键词： Room temperature.,Gas sensor,Reduce graphene oxide,Ammonia,Au nanoparticle,Titanium dioxide,UV illumination
更新于2025-09-23 15:23:52
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Copper-doped hybrid Agx–Auy@ZnO nanoparticles and their enhanced photocatalytic activities
摘要： In this paper, we report on the simple polyol synthesis of copper-doped hybrid Agx–Auy@ZnO photocatalysts. The obtained samples have been characterized by X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, transmission electron microscopy and an N2 adsorption study. The experiment results show that Ag, Au and Ag–Au alloy nanoparticles (NPs) successfully load onto the surface of the assembled Cu-doped ZnO. The photocatalytic performances of Cu-doped Agx–Auy@ZnO nanomaterials have been tested using diuron herbicide as a model contaminant under simulated solar light irradiation. The addition of Ag and/or Au nanoparticles to doped ZnO was strongly beneficial to the rate constant displaying a volcano-like pattern as a function of the Ag and Au content. A maximum pseudo-first-order rate constant of 18.55 × 10?3 min?1, 22.70 × 10?3 min?1 and 24.74 × 10?3 min?1 was achieved on Cu-doped Ag0.3@ZnO, Au0.5@ZnO and Ag0.5–Au0.3@ZnO respectively. The Cu-doped Ag0.5–Au0.3@ZnO bimetallic nanoparticles show the highest photocatalytic activity due to the synergistic effect by effective electron transfer.
关键词： Hybrid photocatalyst,Copper-doped,Diuron,Water treatment,Polyol process,One pot,Zinc oxide,Gold,Photocatalysis,Solar light,Silver
更新于2025-09-23 15:23:52
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Optical properties of amine-functionalized graphene oxide
摘要： Important applications of graphene oxide (GO) its derivatives have been found in several areas: energy materials, water treatment, environmental, catalytic, photocatalytic, and biomedical technologies. Among them, the application of GO in optical biosensors has attracted ever-increasing interest in the past few years. In the present work, GO was amine-functionalized by a solvent-free one-step method with two aromatic amines: 1-aminopyrene (AP), and 2-aminofluorene (AF); and one aliphatic amine 1-octadecylamine (ODA). Particle size was estimated by field emission-scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). Optical properties have been evaluated by application of photoluminescence (PL), FTIR, UV–VIS, and Raman spectroscopy. As a result, this study offers an efficient way to tune the optical properties due to their amine functionalization, favoring the development of optoelectronic and biological applications using graphene-based materials in the future.
关键词： Amine functionalization,Optical properties,Sensors,Graphene oxide
更新于2025-09-23 15:23:52
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Modeling and optimization of characterization of nanostructure anodized aluminium oxide membranes
摘要： This study indicates the importance of statistical analysis and modeling to investigate the synthesis and optimization of anodized aluminium oxide (AAO) properties for template-assisted synthesis of nanostructure particles. The response surface methodology was used to optimize pore size and porosity of AAO. The impacts of four main parameters including type of acidic electrolyte, concentration of acid, bath temperature and electrical potential of anodization on characterization of AAO were investigated. Statistical analysis showed that the linear and quadratic terms of these variables had significant effects. Based on the statistical analysis, a possible mechanism of the anodization was proposed. The proposed mechanism helped us to develop an analytical model. The analytical model could predict the experimental results with an appropriate accuracy. Results indicated the rate-limiting reaction in anodization process is water dissociation which was conducted at the pore bottom of the AAO. In addition, concentrated electrical field at pore base induced water splitting so that the activation energy of water dissociation decreased ten times and reached to 9898.5 J/mol.
关键词： Statistical analysis,Anodized aluminium oxide,Electrochemical synthesis,Pore perforation,Nanoporous materials
更新于2025-09-23 15:23:52
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Evidence and Influence of Copper Vacancies in p-Type CuGaO <sub/>2</sub> Mesoporous Films
摘要： Delafossite CuGaO2 nanocrystals were hydrothermally synthesized and characterized spectroscopically and electrochemically as mesoporous thin films. The nanocrystals demonstrate a preferred orientation within the film structure, as shown by enhancement of the (00l) peaks via two-dimensional powder X-ray diffraction. Annealing conditions of low and high temperature (i.e., 100?300 °C), with oxygen and/or argon atmospheres, were investigated, and the resulting effect on the thin film electrochemistry was measured. Cyclic voltammetry showed an increase in non-faradaic current with higher annealing temperatures and demonstrated a quasi-reversible redox feature (E1/2 = 0.1 V vs Fc+1/0). This feature is assigned to a CuII/CuI redox couple associated with surface defects. X-ray photoelectron and energy dispersive spectroscopies provide evidence for CuII surface defects and copper vacancies. Electrochemical impedance spectroscopy revealed that CuGaO2 films were highly conductive with σ ～ 10?5 Ω?1 cm?1, consistent with a large density of hole carriers induced by copper vacancies. The significance of synthesis, film preparation, and annealing conditions on the presence of surface defects and large hole densities is discussed. The prevalence of such defects in delafossite CuGaO2 is expected to have a large impact on the use of this material as a hole transport layer in solar cell architectures.
关键词： p-type metal oxide,delafossite,hole transport,heterojunction solar cell,CuGaO2
更新于2025-09-23 15:23:52