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Studies on the microstructure,optical and electrical properties of organic microcavity devices based on a porous silicon reflector

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Science china(Technological Sciences) 2005年第2期48卷 191-201页

作者： XIONG Zuhong1, FAN Yongliang2. ZHAN Yiqiang2. ZHANG Songtao2. DING Xunmin2.& HOU Xiaoyuan2.1. School of physics, Southwest china-Normal {2., Chongqing 400715, china 2. surface physics laboratory (National key laboratory), fudan university, shanghai 2.0433, china 1. School of physics Southwest China-Normal University 400715 Chongqing China 2. surface physics {2. (National key {2.) Fudan University 200433 Shanghai China

A novel type of microcavity organic light-emitting diode based on a porous silicon distributed Bragg reflector (PS-DBR) has first been achieved and its microstructure, optical, and electrical properties have also been investigated in detail. The microcavity is made up of the central active organic multilayer sandwiched between a top silver film and a bottom PS-DBR, formed by electrochemical etching of p++-Si substrate. The field- emission scanning electron microscopy cross-section images show the nanometer-scale layered structure and flat interfaces inside the microcavity. The reflectivity (relative to an Al mirror) of the PS-DBR is up to 99%, and the stopband is about 160 nm wide. Resonant cavity mode appears as a tip in the reflectivity spectrum of the Si-based organic multilayer films, which is a symbol that the Si-based organic multilayer structure is indeed a microcavity. The peak widths of the electroluminescence (EL) spectra from the cavities emitting green and red light are greatly reduced from 85 nm and 70 nm to 8 nm and 12.nm, respectively, as compared with those measured from non-cavity structures. Note that the EL emission from the cavity devices is single-mode, and the off-resonant optical modes are highly suppressed. Moreover, increases of a factor of about 6 and 4 of the resonant peak intensity from the cavities emitting green and red light are also observed, respectively. In addition, the current-brightness-voltage characteristics and effect parameters on the lifetime of the cavity devices are also discussed. The present technique for obtaining enhanced EL emission from Si-based organic microcavity may also be another novel effective method for realizing Si-based optoelectronics device integration.

关键词： electrochemical etching, Si-based microcavity, electroluminescence, organic light-emitting diodes.

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Density-functional theory study of the effect of pressure on the elastic properties of CaB_6

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Chinese physics B 2013年第7期22卷 420-425页

作者：韩晗 surface physics {2. (National key {2.) Key Laboratory of Computational Physical Sciencesand Department of PhysicsFudan University

Under high pressure, the long believed single-phase material CaB6 was latterly discovered to have a new phase tI56. Based on the density-functional theory, the pressure effects on the structural and elastic properties of CaB6 are obtained. The calculated bulk, shear, and Young’s moduli of the recently synthesized high pressure phase tI56-CaB6 are larger than those of the low pressure phase. Moreover, the high pressure phase of CaB6 has ductile behaviors, and its ductility increases with the increase of pressure. On the contrary, the calculated results indicate that the low pressure phase of CaB6 is brittle. The calculated Debye temperature indicates that the thermal conductivity of CaB6 is not very good. Furthermore, based on the Christoffel equation, the slowness surface of the acoustic waves is obtained.

关键词： density-functional theory elastic properties pressure effects acoustic properties

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Preparation of InSb nanocrystals embedded in SiO_2.thin films

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Chinese Science Bulletin 1998年第19期43卷 1610-1615页

作者： ZHU Kaigui 1, SHI Jianzhong 1, WEI Yanfeng 2.and ZHANG Lide 1 1. Institute of Solid State physics, Chinese Academy of Science, Hefei 2.0031, china 2. State {2. laboratory of surface physics, fudan university, shanghai 2.0433, china Institute of Solid State physics Chinese Academy of Science Hefei China State key laboratory of {2. physics Fudan University Shanghai China

InSb nanocrystals embedded in SiO 2.thin films were prepared by rf magnetron cosputtering technique. THe observation by transmission electron microscope showed that InSb nanocrystals dispersed uniformly in SiO-2.matrices. InSb nanocrystals with different sizes can be obtained by changing the annealing condition. The average size of InSb nanocrystals depended on annealing temperature and time, but not on the t 1/3 rules. X-ray photoelectron spectroscopy and X-ray diffraction were also applied to the analyses of the composite thin films.

关键词： InSb nanocrystals radio-frequency sputtering quantum confinement.

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PIXE and INAA studies on ancient potteries from Guangfulin relics in shanghai

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Progress in Natural Science:Materials International 2007年第11期17卷 1348-1356页

作者： Lin Jiawei1, Cheng Huansheng1, Zhang Zhengquan1, Zhang Bin1, Feng Songlin2. Song Jian3, Gao Menghe4 and Zhu Dan1(1. Applied Ion Beam physics laboratory, {2. laboratory of the Ministry of Education, Institute of Modern physics, fudan university, shanghai 2.0433, china 2. {2. laboratory of Nuclear Analytical Techniques, Institute of High Energy physics, Beijing 100039, china 3. {12. Museum, {12. 2.0003, china 4. Department of Cultural Heritage and Museology, fudan university, shanghai 2.0433, china) Applied Ion Beam physics laboratory Key Laboratory of the Ministry of Education Institute of Modern Physics Fudan University Shanghai 200433 China key laboratory of Nuclear Analytical Techniques Institute of High Energy Physics Beijing 100039 China shanghai Museum Shanghai 200003 China Department of Cultural Heritage and Museology Fudan University Shanghai 200433 China

This paper reports the study of ancient potteries unearthed from the Guangfulin site in shanghai. From the external features of these potteries, archeologists can classify them into two different cultural types: Liangzhu culture (local culture) and a new culture which might be derived elsewhere, but they can not recognize whether they were produced in the same place. Proton induced X-ray emission (PIXE) and instrumental neutron activation analysis (INAA) were used to measure the chemical compositions of the samples and the results were analyzed using multivariate statistics. We found that the two methods can complement each other and their database can be mutually referenced in the study of ancient potteries. Experimental results show that the compositions of the potteries from the two cultural types are different, which means that the materials for ancient potteries of new culture originate from elsewhere. This supports the archaeologists’ speculation that a group of ancient people migrated to shanghai from some other places 4000 years ago.

关键词： PIXE INAA factor analysis Guangfulin ancient pottery

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TURNING-OVER OF THE ELECTRIC DIPOLE IN A POLYMER

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Chinese Journal of Polymer Science 2001年第6期19卷 573-578页

作者： Guang-qi Li Xin Sun and Sheng Li State key laboratory of {2. physics and Research Center for Theoretical physics, fudan university shanghai 2.0433, china National laboratory of Infrared physics, shanghai Institute of Technical physics,shanghai 2.0083, china fudan Univ State Key Lab Surface Phys Shanghai 200433 Peoples R China fudan Univ Res Ctr Theoret Phys Shanghai 200433 Peoples R China Acad Sinica Shanghai Inst Tech Phys Natl Lab Infrared Phys Shanghai 200083 Peoples R China

The transition from the biexciton to the exciton can turn over the direction of the electric dipole of a polymericmolecule. This turning-over action combined with the photoinduced polarization reversion can be used as a switch. Theswitching speed is governed by the relaxation time of the turning-over process, which can be determined by a dynamicalsimulation.

关键词： exciton biexciton electric dipole switch relaxation

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Interfacial processes in small molecule organic solar cells

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 288-300页

作者： LI WenBin,SONG QunLiang,SUN XiaoYu,WANG MeiLiang,WU HuanRong,DING XunMin & HOU XiaoYuan surface physics {2. (National key {2.),fudan university,shanghai 2.0433,china 1. surface physics {2. (National key {2.) Fudan University Shanghai 200433 China

This paper presents an overview of the recent progress of small molecule organic solar cells mainly based on the previous worksof our group. We will mainly focus on the interfacial processes in the cells. The dissociation of excitons at electrode/organic andorganic/organic interfaces can be directly observed by transient photovoltage measurements. A simple model including dissociationof excitons at the interface and drift of free carriers in the built-in field is proposed to explain the observed signals of transientphotovoltage. Besides exciton-blocking and preventing damage due to cathode evaporation,blocking permeation of oxygen and/orwater molecules and modulating the built-in field are proposed as functions of the buffer layer between C60 and Al. By the use ofthe inverted structure,a shelf lifetime of over 1500 h is achieved for unencapsulated small-molecule organic solar cells.

关键词： organic solar cell interface organic semiconductor

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Ultrafast excitation relaxation in light-harvesting complex LH2.from *** 601

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Science china Chemistry 2004年第3期47卷 192-199页

作者： GUO Lijun1,2. LIU Yuan3, LIU Weimin2. GUO Junhua1, XU Chunhe3 & QIAN Shixiong2.1. School of physics and Information Optoelectronics, Henan university, Kaifeng 475001,{2. 2. physics Department, fudan university, shanghai 2.0433,{2. 3. shanghai Institute of Plant Physiology, Chinese Academy of Sciences, shanghai 2.0032.{2. 1. School of physics and Information Optoelectronics Henan University 475001 Kaifeng China 2. physics Department Fudan University 200433 Shanghai China 3. shanghai Institute of Plant Physiology Chinese Academy of Sciences 200032 Shanghai China

The energy relaxation and kinetic evolution of transient spectra of bacteriochloro- phylls (BChls) in light-harvesting complex LH2.from Rb. sphaeroides 601 were investigated using femtosecond pump-probe technique. Upon 783 nm excitation, the energy at B800 BChls ex-periences an intramolecular redistribution with 0.35 ps time constant before transferring to B850 BChls. With tuning the excitation wavelength, the dynamical evolution of excited BChls was clearly observed, which indicates an obvious competition between the ground state bleaching and excited state absorption (ESA) of BChls involved and an isosbestic point near 818 nm, and also demonstrates that from the lower electronic excited state of B800 BChls to the higher exci-tonic state of B850 BChls is an efficient routine for energy transfer. The excitation energy in higher excitonic states of B850 BChls relaxes rapidly to the next lowest excitonic state by inter-conversion, delocalization to adjacent molecular, populating the lowest excitonic state and the change of molecular conformation.

关键词： photosynthesis, light-harvesting complex, energy transfer, ultrafast, dynamics, purple bacteria.

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Dynamics of Primary Events in the Photocycle of Excited Bacteriorhodopsin

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Acta Biochimica et Biophysica Sinica 2004年第11期36卷 724-728页

作者： Jun-Jun LU, Ming MING, Yi YANG, Jia WU, Bo LI, Jian-Dong DING, Qing-Guo LI, and Shi-Xiong QIANDepartment of physics, fudan university,{2., china Department of Macromolecular Science, key laboratory of Molecular Engineering of Polymers, fudan university,{2., china Department of Physiology and Biophysics, School of Life Sciences, fudan university,{2., china Department of physics Fudan University Shanghai 200433 China

Transient dynamic behavior of the excited bacteriorhodopsin (BR), which was isolated from the strain H. salinarum, was studied at excitation wavelength from 585 to 639 nm. With the one-color femtosecond (fs) pump-probe technique, we revealed the primary events in BR's photocycle that took place in an ultrafast time scale. From the analysis of the decay components of the dynamical traces, it was evident that the isomerization of the retinal

关键词： bacteriorhodopsin transient dynamics primary events femtosecond laser pump-probe technique

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Generation of large fifth-order nonlinear phase shifts by use of lossless χ^((2.) cascaded nonlinear processes

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Science china(physics,Mechanics & Astronomy) 2004年第1期47卷 1-7页

作者： XU Guang1, QIAN Liejia2. WANG Tao2. FAN Dianyuan1,2.& LI Fuming2.1. shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, shanghai 2.1800,{2. 2. State key laboratory for Advanced Photonic Materials and Devices, fudan university, shanghai 2.0433,{2. Correspondence should be addressed to Xu Guang (email: xuguany@***) Received March 9, 2.03 1. shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences 201800 Shanghai China 2. State key laboratory for Advanced Photonic Materials and Devices Fudan University 200433 Shanghai China

It is shown that the cascaded fifth-order nonlinear phase shifts will increase with energy loss in the cascaded processes. Essentially different from the multi-photon absorption accompanied with inherent material nonlinearities, the loss of fundamental wave in a cascaded process is controllable and suppressible. By introducing difference frequencies generated from the reaction between the fundamental and its second harmonic after the cascaded processes, the fundamental wave can be free of energy loss, while the large cascaded fifth-order nonlinear phase shift is maintained.

关键词： cascaded nonlinear phase shifts, phase mismatching, harmonic conversions.

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Proton induced X-ray emission (PIXE) analysis of sources of porcelain body of Ru Guan and Jun Guan porcelains

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Science china(physics,Mechanics & Astronomy) 2006年第4期49卷 411-420页

作者： LI Guoxia1, ZHAO Weijuan1, LI Rongwu2. SUN Hongwei1, GUO Min1, WANG Yanfang1, LIU Hui1, ZHAO Qingyun3, SUN Xinmin3, ZHAO Wenjun3 & CHENG Huansheng4 1. Faculty of Physical Engineering, Zhengzhou university, Zhengzhou 450052. china 2. Department of {2., Beijing Normal university, Beijing 100875, china 3. Institute of Cultural Relic and Archaeology of Henan Province, Zhengzhou 450000, china 4. Institute of Modern {2., fudan university, shanghai 2.0433, china Faculty of Physical Engineering Zhengzhou University Zhengzhou 450052 China Department of physics Beijing Normal University Beijing 100875 China Institute of Cultural Relic Archaeology of Henan Province Zhengzhou 450000 China Institute of Modern physics Fudan University Shanghai 200433 China

34 samples of Ru Guan porcelain body and 50 samples of Jun Guan porcelain body (both kinds being in different body colors) were selected with the purpose of finding out the source of raw materials and their classification relationship so as to search for ways of non-destructive discrimination. Proton induced X-ray emission (PIXE) has been applied to these samples to determine their chemical elements. The data of seven major chemical elements collected from these samples were further studied through fuzzy cluster analysis. Results indicate that the origin of raw materials of Jun Guan porcelain body samples is comparatively more concentrated in certain places, while that of Ru Guan porcelain body samples is scattered about. The places of origin of raw materials of the majority of Ru Guan and Jun Guan porcelain body samples have something in common, but some differences still exist. It might be an important way for non-destructive discrimination among Ru Guan and Jun Guan porcelains by combining PIXE with fuzzy cluster analysis.

关键词： Ru Guan and Jun Guan porcelain, source of porcelain body, PIXE, fuzzy cluster analysis, non-destructive discrimination.

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