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quantum size effect ON PHOTOCATALYSIS OF NANOMETER SEMICONDUCTOR

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Chinese Journal of Catalysis 1995年第1期 1-2页

作者： Wu, Ming Li, Wen-zhao Gu, Wan-zhen Zhao, Shi-ting Zhu, Xiang-wei and Wang, Fu-dong(Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023)

Colloidal semiconductor is of interest as photocatalyst for various pro-cesses.A particular attention has been given to the so-called Q-particles ofsemiconductor witn respect to a“quantum size effect”[1].Recently,we re-ported that 1 nm ZnS particles could be obtained by embedding them Into β-cyclodextrin( BCD) cavities[2]and the resulting ZnS/BCD inclusion complexshowed much higher efficiency in simultaneous photocatalytic production ofhydrogen and ethylene glycol from aqueous methanol solution[3].In thiswork,we briefly present experimental evidence for the size quantization ef-fect of such small ZnS particles on the photocatalysis.

关键词： nanometer semiconductor photocatalysis quantum size effect

Confinement of gold quantum dot arrays inside ordered mesoporous silica thin film

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Journal of Semiconductors 2009年第12期30卷 1-4页

作者：池雅庆仲海钦张学骜方粮常胜利 School of Computer National University of Defense Technology School of Science National University of Defense Technology

Periodic disposed quantum dot arrays are very useful for the large scale integration of single electron devices. Gold quantum dot arrays were self-assembled inside pore channels of ordered amino-functionalized mesoporous silica thin films, employing the neutralization reaction between chloroauric acid and amino groups. The diameters of quantum dots are controlled via changing the aperture of pore channels from 2.3 to 8.3 nm, which are characterized by HRTEM, SEM and FT-IR. UV-vis absorption spectra of gold nanoparticle/mesoporous silica composite thin films exhibit a blue shift and intensity drop of the absorption peak as the aperture of mesopores decreases, which represents the energy level change of quantum dot arrays due to the quantum size effect.

关键词： gold quantum dot array mesoporous silica quantum size effect single electron device

ZnO@Porous Media,Their PL and Laser effect

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Journal of Materials Science & Technology 2008年第4期24卷 495-511页

作者： C.Bouvy Laboratory of Inorganic Materials Chemistry The University of Namur(FUNDP)61 rue de BruxellesB-5000 NamurBelgium

Optoelectronic nanocomposites are a new class of materials, which exhibit very interesting and particular properties and attract a growing attention due to their potential applications in information storage and optoelectronic devices. Zinc oxide, ZnO, is one of the most interesting binary semiconductor （3.37 eV） with very important optical properties, which can be used in the fields such as short wavelength lasers, blue light emitting diodes, UV detectors, gas sensors, etc. This paper reviews the very recent progress in the prepa- ration of silica-based ZnO nanocomposites. After an introduction reviewing the theoretical background, the article will begin with a survey of the optical properties and the quantum size effect （QSE） of ZnO/SiO2 nanocomposites prepared by the inclusion of ZnO nanoclusters inside silica mesoporous materials. The second part will focus on one of the most interesting properties of ZnO/SiO2 nanocomposites, which is the random lasing effect after one- and two-photon excitation. The final part will deal with the introduction of ZnO nanoparticles inside microporous zeolites and the observation of QSE. For comparison, the photoluminescence （PL） and QSE properties of ZnS nanoparticles occluded in mesoporous media are also described. New potential applications will be discussed since short-wavelength devices are required by industry to design, for instance, new information storage supports and biolabelling devices.

关键词： ZnO nanoparticles Microporous and mesoporous materials quantum size effect Random lasing effect

Self—Organization of CdS Nanoparticles in Polystyrene Film

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Chinese Physics Letters 2002年第6期19卷 871-874页

作者：梁海春王树峰等 MaterialsScienceInstitute KeyLaboratoryforPolymericCompositeandFunctionalMaterialsofMinistryofEducationZhongshanUniversityGuangzhou510275 StateKeyLaboratoryforMesophysics Peking

Self-organization of nano-CdS particles in polystyrene can be observed by encapsulating the particles with n-dodecyl mercaptan owing to a strong electron transfer interaction between the modified CdS nanoparticles and aliphatic carbons in polystyrene. Consequently, ultraviolet/visible absorption edge of the treated nano-CdS/polystyrene composites is further blueshifted in addition to the shift caused by the quantum size effect, and the fluorescence emission peak of the composite becomes redshifted and narrow

关键词： Composites Organizations Redox processes Shift narrowing Sulfhydryl Compounds quantum size effect Polystyrenes self-organization electron transfer

Can Nano-Particle Melt below the Melting Temperature of Its Free Surface Partner?

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Communications in Theoretical Physics 2015年第2期63卷 249-254页

作者：眭晓红王宗国康凯覃绍京王垂林 State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Computer Network Information Center Chinese Academy of Sciences Science and Technology on Surface Physics and Chemistry Laboratory China Center of Advanced Science and Technology

The phonon thermal contribution to the melting temperature of nano-particles is inspected. The discrete summation of phonon states and its corresponding integration form as an approximation for a nano-particle or for a bulk system have been analyzed. The discrete phonon energy levels of pure size effect and the wave-vector shifts of boundary conditions are investigated in detail. Unlike in macroscopic thermodynamics, the integration volume of zero-mode of phonon for a nano-particle is not zero, and it plays an important role in pure size effect and boundary condition effect. We find that a nano-particle will have a rising melting temperature due to purely finite size effect; a lower melting temperature bound exists for a nano-particle in various environments, and the melting temperature of a nano-particle with free boundary condition reaches this lower bound. We suggest an easy procedure to estimation the melting temperature, in which the zero-mode contribution will be excluded, and only several bulk quantities will be used as input. We would like to emphasize that the quantum effect of discrete energy levels in nano-particles, which is not present in early thermodynamic studies on finite size corrections to melting temperature in small systems, should be included in future researches.

关键词： nano-particle quantum size effect boundary condition effect size-dependent melting

Photoluminescence Studies on Ferric Oxide Ultrafine Particles

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Chemical Research in Chinese Universities 1994年第2期10卷 146-148页

作者： ZHANG Yan AI Xi-cheng XIAO Liang-zhip FEI Hao-sheng and LI Tie-jin (Department of Chemistry , Department of Physics, Jilin University,Changchun, 130023 )

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关键词： Ultrafine particles quantum size effect Surface modification Photo-luminescence

Photocatalytic Decolorization of Methylene Blue on the Nanosized Ti02 -Polymer Composites

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Chemical Research in Chinese Universities 2001年第Z1期17卷 246-247页

作者： SU Bi-tao College of Chemistry and Engineering Northwest Normal University College of Chemistry and Engineermg Lanzhou University College of Chemistry and Engineering Northwest Normal University College of Chemistry and Engineermg Lanzhou University

Titanium dioxide semiconductor systems with excellent stability of photo-electric chemistry, no poison, cheap, and high separation efficiency of photogenerated charges, consequently, high photocatalytic activity, have been the subject of extensive investigation because of their promise in the photovoltaic[1], photocatalytic[2], and battery applications[3]. The efficiencies of these materials in photovoltaic and photocatalytic applications depend strongly upon the trapping and recombination energetics, i.e., electrons and holes and the conversion of light. Nanosized TiO2 particles present much higher photocatalytic activity due to larger effective surface areas, higher densities of. surface states, shorter distance of photogenerated charges from inner to the surfaces of TiO2 particles resulting in higher separation efficiency of electron-hole pairs, and quantum size effect.

关键词： photocatalytic activity separation efficiency quantum size effect surface areas densities of

Green Synthesis of CdSe quantum Dots with Tunable Photoluminescent Properties

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Journal of the Chinese Ceramic Society 2014年第1期1卷 53-58页

作者： GAO Bing SHEN Chao YUAN Shuanglong YANG Yunxia CHEN Guorong Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and EngineeringEast China University of Science and Technology

The CdSe quantum dots（QDs） were synthesized with water phase Se precursor and non-toxic glycerol as a solvent of Cd precursor. According to the analysis by X-ray diffraction（XRD）, the phases of the product are pure. The particle size of the monodispersive QDs product determined by high resolution transmission electron microscopy（HRTEM） is 3.2 nm4.5 nm. Furthermore, compared to the CdSe bulk material, the band gap of QDs exhibits a blue shift, indicating that the size of the QDs product is in nanoscale. In addition, the photoluminescent spectra of CdSe QDs show red shifts from 529 nm to 591 nm when the size of CdSe QDs increases, due to the quantum size effect. The quantum yield of CdSe QDs is calculated to be 50.53%, which is greater than that of the CdSe QDs synthesized by other water phase methods.

关键词： Cd Se quantum dots(QDs) green synthesis photoluminescent properties quantum size effect quantum yield(QY)

The nonlinear absorption of carbon quantum dots under the picosecond laser pulse

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The nonlinear absorption of carbon quantum dots under the pi...