biological applications of photoluminescent semiconductor quantum dots

... SYNTHESIS OF CDTE AND PBS SEMICONDUCTOR QUANTUM DOTS AND THEIR BIOLOGICAL AND PHOTOCHEMICAL APPLICATIONS Xing Zhang, M.S The University of Texas at Arlington, 2010 Supervising Professor: Wei Chen Semiconductor ... science 1.2 Quantum Dots Quantum dots, the so-called nanocrystals, are nano-sized semiconductor particles composed of II-VI group or III-V main group elements Normally, the size of the quantum dots ... or sputtering Quantum dots can be self assembled on a thin film by chemical vapor deposition (CVD) 1.4 Quantum Dots Biological Applications Quantum dots are small, compared with biological tissues,...

Ngày tải lên: 28/04/2014, 15:48

... measurements of the QD-EAM photocurrent is extracted with the use of the semiconductor parameter analyzer (HP/Agilent 4156B) The optical transmission measurement setup consists of a superluminescent ... also see the broadening of the peak This is due to field ionization of electrons and holes with increasing E-field [23] Due to the lack of inversion symmetry as a result of their asymmetric shape, ... dots Note that PC measurement can be employed to investigate both the quantum confined Stark effect (QCSE) and field-dependent absorption changes of the active region [30] However, extraction of...

Ngày tải lên: 22/06/2014, 01:20

... STUDIES OF TWO DIMENSIONAL CARBON NANOSTRUCTURES AND SEMICONDUCTOR QUANTUM DOTS Ni Zhenhua (B Sc Shanghai Jiao Tong University) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF ... Haomin and Assoc Prof Wu Yihong from Department of Electrical and Computer Engineering of NUS, Dr Pan Hui from Department of Physics of NUS, and Assoc Prof Han Mingyong from Institute of Materials ... electron state of such system This part of work provides a good model for the study of structural stability of semiconductor QDs viii List of Figures Figure 2.1 Schematic spectrum of light scattering...

Ngày tải lên: 13/09/2015, 21:36

... among semiconductor quantum dots induced by a metal nanoparticle Yong He and Ka-Di Zhu∗ Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics, ... metal nanopartities (MNPs), semiconductor quantum dots (SQDs) and nanowires can be constructed for the applications in photonics and optoelectronics [1,2] Studies of these nanostructures are ... have shown a decrease of the exciton lifetime of SQD placed in the vicinity of MNP The decrease is related to the distance between SQD and MNP as a result of the coupling of the exciton and SPP...

Ngày tải lên: 20/06/2014, 20:20

... order of magnitude as can be seen in Figure Because of this difference, several authors [5,6,8] used the strong-confinement limit as a satisfactory approximation in the case of small quantum dots ... Coulomb interaction decreases, as the energy of the quantum state increases The final result is a blue-shift of the OR and SHG peaks of the order of meV for both ω0 = × 1013 s-1 and ω0 = × 1014 ... blue-shift of the energy peaks of the order of several meV in the studied spectra These results were found for two quantum dot sizes, in the first one the characteristic quantities of the harmonic...

Ngày tải lên: 21/06/2014, 04:20

... among semiconductor quantum dots induced by a metal nanoparticle Yong He and Ka-Di Zhu∗ Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics, ... metal nanopartities (MNPs), semiconductor quantum dots (SQDs) and nanowires can be constructed for the applications in photonics and optoelectronics [1,2] Studies of these nanostructures are ... have shown a decrease of the exciton lifetime of SQD placed in the vicinity of MNP The decrease is related to the distance between SQD and MNP as a result of the coupling of the exciton and SPP...

Ngày tải lên: 21/06/2014, 17:20

... blue shift of the quantum dots in living cells: effect of oxidation by singlet oxygen J Am Chem Soc 2006, 128:13396-13401 Fu Y, Han TT, Luo Y, Ågren H: Multiphoton excitation of quantum dots by ... H: Dynamic analysis of multiple-photon optical processes in semiconductor quantum dots J Phys Condens Matter 2006, 18:9071-82 Zhang LW, Monteiro-Riviere NA: Mechanisms of quantum dot nanoparticle ... Lin L, Chen P, Liu Y, Tang GO, Wu J, Yue Y, Dai N: Design of semiconductor CdSe core ZnS/CdS multishell quantum dots for multiphoton applications Appl Phys Lett 2007, 90(3):173102 Zhang Y, He...

Ngày tải lên: 11/08/2014, 00:22

... toxicity of two types of widely used nanomaterials (TiO2 and CdTe) was evaluated [7] No data is available concerning toxicology of Quantum Dots (QDs) in higher plant cells [8] QDs are inorganic semiconductor ... setup: mL of suspension culture with a final concentration of NBT of 60 nM (negative control), mL of suspension culture treated 45°C for 20 minutes with a final concentration of NBT of 60 nM (positive ... impact of CdSe/ZnS Quantum Dots in cells of Medicago sativa in suspension culture Journal of Nanobiotechnology 2010 8:24 Submit your next manuscript to BioMed Central and take full advantage of: ...

Ngày tải lên: 11/08/2014, 00:22

... on Semiconductor Quantum dots: 1.1.1 Synthesis of Monodisperse QDs : 1.1.2 Surface Structure of the quantum dots: 1.1.2.1 Organically Capped Quantum Dots 1.1.2.2 Inorganically Passivated Quantum ... important people of life My Mom and wife vi Table of Contents TABLE OF CONTENTS TITLE PAGE DECLARATION PAGE ACKNOWLEDGEMENTS TABLE OF CONTENTS SUMMARY LIST OF TABLES LIST OF FIGURES LIST OF ABBREVIATIONS ... Quantum Dots 1.1.3 Properties of quantum Dots: 1.1.3. 1Quantum Confinement Effects and Band-Gap 1.1.3.2 Luminescence Properties 11 1.2 Shape control beyond spherical dots: 12 1.2.1 Importance of the...

Ngày tải lên: 08/09/2015, 19:58

... CdSe QUANTUM DOTS 70 4.1 Introduction 70 4.2 Synthesis and characterization of CdSe quantum dots 74 4.3 TPA coefficients in CdSe quantum dots 79 4.4 Auger process following TPA in CdSe quantum dots ... structure of group II-VI quantum dots based on PB model 37 2.2.1 Band structure of group II-VI semiconductors 37 2.2.2 Wave functions of group II-VI semiconductors 38 2.3 TPA in strong confinement quantum ... characterization of CdTe quantum dots 95 5.3 Experimental study on the TPA in CdTe quantum dots 99 5.4 Theoretical study on the TPA in CdTe quantum dots 103 5.4.1 Wave functions and energy levels in CdTe quantum...

Ngày tải lên: 14/09/2015, 08:38

... PHOTOLUMINESCENCE IN DOPED SEMICONDUCTOR QUANTUM DOTS AND HETERO-NANOSTRUCTURES”, submitted for the degree of Joint Doctor of Philosophy in Physical Sciences to Indian Institute of Technology Madras ... degree or diploma Prof C Vijayan Prof Wei Ji (Research Guide) (Research Guide) Photonics Laboratory Department of Physics Department of Physics Faculty of Science Indian Institute of Technology Madras ... and NUS authorities, especially Prof Markandeylu (former HOD, Dept Of Physics, IITM), Prof Sunil Kumar (HOD, Dept of Physics, IITM) and Prof B.V.R Chowdhary (Dept of Physics, NUS) for giving me...

Ngày tải lên: 17/09/2015, 17:17

... The absorbance of the formazen product was then measured at a wavelength of 570 nm Four groups of MTT tests were done for each quantum dots concentration The values of MTT assay of labeled cells ... size, which decreases not only the monochromaticity of the fluorescence but also the quantum yields of the QDs In our case, the quantum yields of the as-synthesized CdSe cores are around 2–3% In ... promising applications as fluorescent biological labels Human embryonal kidney cell line is chosen as typical kind of human cells to demonstrate the promising applications as fluorescent biological...

Ngày tải lên: 21/06/2014, 08:20

... Preface Quantum dots are one of the most promising types of nanoparticles, which are exceptionally useful for variety of new applications Because of their unique properties Examples of such applications ... to an upper quantum dot layer Fig 13 Transmission electron microscopy image of seven stacked layers of InAs quantum dots separated by 10 nm of GaAs The increased size of quantum dots is predominantly ... increasing Capping of InAs/GaAs Quantum Dots for GaAs Based Lasers 29 capping thickness More detailed study of the impact of the capping layer thickness on the electronic structure of quantum dots can...

Ngày tải lên: 26/06/2014, 23:20

... toxicity of nanocrystal quantum dots depend on their surface modification Nano Lett 2004, 4:2163-2169 38 Derfus AM, Chan WCW, Bhatia SN: Probing the cytotoxicity of semiconductor quantum dots Nano ... exposure of CdTe quantum dots on PC12 cellular activity and the determination of optimum nontoxic concentrations for biological use Journal of Nanobiotechnology 2010 8:7 Page 16 of 16 Submit your ... Imaging of Quantum Dots Encapsulated in Phospholipid Micelles Science 2002, 298:1759-1762 Gao X, Cui Y, Levenson RM, Chung LWK, Nie S: In vivo cancer targeting and imaging with semiconductor quantum...

Ngày tải lên: 11/08/2014, 00:22

... tunable emission of CdSe quantum dots (A) F luorescence image of a series quantum dots excited with an ultraviolet lamp T particle he diameters are shown (B) S chematic illustration of the relative ... Alivisatos AP Semiconductor clusters, nanocrystals, and quantum dots Science 271(5251), 933–937 (1996) • Outstanding review paper on quantum • dot (QD) physics 242 Murphy CJ, Coffer JL Quantum dots: ... Mol Diagn 6(2), (2006) Multicolor quantum dots for molecular diagnostics www future-drugs.com 1.2 Time (min) quantum dots 15 10 20 25 30 35 Intensity (au) Quantum dots 0.8 0.6 0.4 0.2 Texas red...

Ngày tải lên: 15/02/2014, 05:20

... Synthesis CdSe quantumdots and determine its size from optical spectra, Advances in Optics Photonics Spectroscopy & Applications V (2008) 517 S.V.Gaponenko, Optical Properties of Semiconductor ... the wavelength of the first excitonic absorption peak (Table 2) The deviation of the peaks in absorption spectra is about 50 nm, which may be due to the difference of surface states of these QDs ... preparation of CdSe quantum dots (QDs) by sol-gel method and investigate their optical properties This is a new route to get CdSe QDs and also very economic We also estimate the average size of QDs...

Ngày tải lên: 14/03/2014, 13:20

... portions of the stationary phase [35,36] High pH-dependence of the retention times of these species has been explained as the consequence of the effects of the changing degree of dissociation of the ... understanding of some aspects of the mechanism of IEC has remained elusive While the current Donnan exclusion interpretation of retention in IEC provides a satisfactory explanation of many aspects of IEC, ... amount of free energy is released due to the formation of the water structure Schematically, the overall process can be described as: Destruction of water structure of the eluent ion Binding of the...

Ngày tải lên: 22/03/2014, 09:20

... height of the quantum dots is mainly concentrated to approximately nm Due to the well known ‘tip effect’ of AFM, the results of AFM measurements cannot describe the precise lateral size of the ... AFM and STEM images of GaSb/In0.53Ga0.47As QDs and histogram of the height of GaSb/In0.53Ga0.47As QDs (a) The AFM image of GaSb/In0.53Ga0.47As QDs, (b) histogram of the height of GaSb/In0.53Ga0.47As ... Strain accumulation in InAs/InxGa1−xAs quantum dots Appl Phys A 2011, 104:257 Wang ZhM, Seydmohamadi Sh, Lee JH, Salamo GJ: Surface ordering of (In, Ga)As quantum dots controlled by GaAs substrate...

Ngày tải lên: 20/06/2014, 20:20

... Synthesis of InP/ZnS For in situ fabrication of InP/ZnS core-shell NQDs, the temperature of the growth solution of InP was lowered after a 10-min growth to 200°C Thirty milligrams of ZDC, ml of TOP, ... Shiang JJ: Covalency in semiconductor quantum dots Chem Soc Rev 1998, 27:65-71 Micic OI, Curtis CJ, Jones KM, Sprague JR, Nozik AJ: Synthesis and characterization of InP quantum dots J Phys Chem 1994, ... III-V semiconductor nanocrystal quantum dots [NQDs] have attracted interest because they have reduced toxicity compared with II-VI compounds However, the study and application of III-V semiconductor...

Ngày tải lên: 20/06/2014, 20:20

... concentration of QDs and geometry of a QD structure Besides tunable IR absorption, QD structures offer wide flexibility for nanoengineering of electron processes via the built-in-dot charge, correlation of ... investigate the potential profiles around dots, we used the nextnano software, which allows for simulation of multilayer structures combined with different materials of realistic geometries in ... number of electrons and number of dopants in the dot In Figure 6, we apply the analysis of our experimental data, obtained from Mitin et al [10], in the framework of this model For fitting of our...

Ngày tải lên: 20/06/2014, 22:20