quantum dots and silica nanoparticles

... stabilized CdTe quantum dots 14 2.3.1.2 L-Cysteine stabilized CdTe quantum dots 14 2.3.1.3 CA stabilized CdTe quantum dots 14 2.3.2 Synthesis of water soluble CdHgTe quantum dots ... photosensitizers 3.3.2 Silica coated CdTe quantum dots response to protoporphyrin-IX In the experimental section we have synthesized silica coated CdTe quantum dots using the TGA stabilized quantum dots The ... stabilized quantum dots are better suited for biological applications such as in vitro imaging and in vivo sensor Mercury doped CdTe quantum dots, namely alloyed HgxCd1-xTe quantum dots have also...

Ngày tải lên: 28/04/2014, 15:48

... cancer marker Her2 and other cellular targets with semiconductor quantum dots Nat Biotechnol 2003, 21:41-46 14 Huo Q: A perspective on bioconjugated nanoparticles and quantum dots Colloids Surf ... excited effectively under ultraviolet band, and their maximum emission peak is about 530 nm, which means the resultant quantum dots is fluorescence-active and could be used as a fluorescent probe ... electrophoresis Characterization of quantum dots Figure The UV absorbance spectrum of QDs The comparison between QDs and superparamagnetic nanoparticle-based hybridization and type-specific PCR was analysized...

Ngày tải lên: 21/06/2014, 01:20

... water-soluble CdSe and CdSe/CdS type-I core–shell QDs with several nanometers in size The one-pot method can provide highquality biocompatible quantum dots without using expensive phosphines and complicated ... the advantages of simpleness, low cost, and green precursor Moreover, the as-received QDs show the tunable and bright PL emission with high quantum yields and high performance as fluorescent biological ... 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 order to passivate their surface trap sites and enhance the quantum yields,...

Ngày tải lên: 21/06/2014, 08:20

... formation of either quantum wires or quantum dots, or even unique island–pit pairs The islands and pits first grow simultaneously as the layer deposition proceeds Both the island height and the pit depth ... QDs, the pits and dots pits cooperative structure growth on InAs(100) substrates by LPE, as well as the interaction and surface morphology of the dots pits combinations are presented and investigated ... QDs and black points to pits The QDs and pits are clearly visible and quite uniformly distributed over the substrate surface Figures 1b, c and 2b– d show that cooperative nucleation of the dots pits...

Ngày tải lên: 22/06/2014, 00:20

... green channel, corresponding to the quantum dots, and part (d) shows the blue channel, corresponding to the nucleus The nucleus and cell membrane, on the one hand, have relatively simple shapes, ... number of voxels corresponding to quantum dots is 2856; given the pixel size and slice spacing, the volume of one voxel is 0.02 µm3, so the total volume for the quantum dots is 58.8 µm3, or about 5% ... committee and recommended by the ATCC (American Type Culture Collection) Quantum dots were prepared and characterized as described previously [16] Rat pheochromocytoma (PC12 cells) and human...

Ngày tải lên: 11/08/2014, 00:22

... Research on Quantum Dots, Nanorods and Hetero-junction nanocomposites 1.2.1 Quantum Dots and Nanorods The optical properties of nanocrystals are determined by their electronic structure (Smith and Nie, ... four band model of semiconductors (Fedorov et al., 1996) In their model, there are a doubly spin degenerate conduction band, a heavy-hole band, a light-hole band and a spin orbit- split band; and ... where e and h are subscripts used for the electron and hole respectively and reh  re  rh The first two terms on the right hand side correspond to the kinetic energies of electron and hole, and...

Ngày tải lên: 17/09/2015, 17:17

... Introduction 1.1 Quantum Dots and Its Properties 1 1.1.1 Introduction to quantum dots 1.1.2 Quantum dots optical properties 1.2 Quantum Dots in Optical Sensing Applications 1.2.1 Anion and small molecules ... several ligands bounding to the surface of ZnS capped CdSe quantum dots (QDs) was studied Different ligands for quantum dots functionalization was synthesized and characterized by ESI-MS, NMR and FT-IR ... 1979 - 34 - Chapter Trolox Functionalized Quantum Dots 3.1 Introduction 3.1.1 Quantum dots and its synthesis Quantum dots (QDs) are spherical semiconductor nanoparticles that composed of atoms from...

Ngày tải lên: 06/10/2015, 21:29

... 19 2.12 Quantum Dots (QDs) 21 2.13 Optical Properties of Quantum Dots (QDs) 21 2.14 Applications of Quantum Dots (QDs) .22 2.15 Limitations of Quantum Dots (QDs) ... extremely narrow bandwidth emission close to the band edge (Green M et al., 1999; Murray CB et al., 2000; Sutherland AJ, 2002) 2.13 Optical Properties of Quantum Dots (QDs) Quantum dots are regarded ... low cost Contrast agents such as organic fluorescent dyes and Quantum Dots (QDs) are often used to promote fluorescence imaging Quantum dots (QDs) are composed of atoms from groups II-VI or III-V...

Ngày tải lên: 13/10/2015, 15:54

... long time reaction and its distribution in particle size is in the broadening range In this article, we report on the preparation of CdSe quantum dots (QDs) by sol-gel method and investigate their ... diffractional angle and k- constant (k = 0,9) The structure and morphologies of the CdSe nanoparticles were characterized using transmission electron microscopy The morphologies of the CdSe nanoparticles ... 0,248R * y y  a   a  * y (1) where E g(a) is the effective band gap of QDs with radius of a, the band gap E g, Bohr exciton radius aB and Bohr exciton energy R * are the specific parameters of...

Ngày tải lên: 14/03/2014, 13:20

... structural and optical properties of type-II GaSb/InGaAs quantum dots [QDs] grown on InP (100) substrate by molecular beam epitaxy Rectangular-shaped GaSb QDs were well developed and no nanodash-like ... This material system shows a promising application on quantum- dot infrared detectors and quantum- dot field-effect transistor Introduction Quantum- size nanostructure materials have always been ... comparatively large bandgap energies and provide a possibility of covering the whole middle and far-infared optical range for photoelectric devices Among these material systems, GaSb/GaAs quantum dot...

Ngày tải lên: 20/06/2014, 20:20

... and B52) and with inter-dot doping (devices B45 and B53) In devices B44 and B52 (Figure 1a), the dopant sheet concentration was 2.7 × 1011 cm-2 and 5.4 × 1011 cm-2, respectively Devices B45 and ... one, two, and three spatial dimensions [13] This simulation tool self-consistently solves Schrödinger, Poisson, and current equations for electrons and holes The conduction and valence bands of ... made measurements related to quantum- dot infrared photodetectors JL and VM conducted the design and analysis of all experiments and modeling results All authors read and approved the final manuscript...

Ngày tải lên: 20/06/2014, 22:20

... in a 1-m monochromator and collected by a cooled InGaAs detector using standard lock-in detection technique Results and discussion The optical properties of the as-grown and annealed QDs on CHP ... photoluminescence; QD: quantum dot; QW: quantum well; TD: threading dislocation; WL: wetting layer Acknowledgements S Thainoi and P Changmoang are acknowledged for maintaining the MBE and PL systems ... contributions CH grew and measured the MBE samples, and interpreted the PL spectra SP provided helps, obtained funding, and supervised the group SK conceived, designed, and supervised the experiments;...

Ngày tải lên: 21/06/2014, 01:20

... [3] CdTe quantum dots (Cdte QDs) have primarily received attentions in biological and biomedical fields due to their high luminescence efficiency, photostability, and broad absorption and narrow ... Access CdTe quantum dots with daunorubicin induce apoptosis of multidrug-resistant human hepatoma HepG2/ADM cells: in vitro and in vivo evaluation Gen Zhang1, Lixin Shi2, Matthias Selke2 and Xuemei ... nm and emission wavelength at 530 nm The drugs DNR and adriamycin were purchased from Sigma-Aldrich (St Louis, MO, USA) The RPMI 1640 cell culture medium was obtained from Gibco BRL (Grand Island,...

Ngày tải lên: 21/06/2014, 03:20

... STEM measurement SZ, TH, and GH conducted the MBE growth JH, WW, and CH coordinated the study WL provided the idea and conceived the study together with ZL All authors read and approved the final ... 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 ... type-II GaSb/GaAs quantum dots Appl Phys Lett 1995, 67:656 10 Alonso-Álvarez D, Alén B, García JM, Ripalda JM: Optical investigation of type II GaSb/GaAs self-assembled quantum dots Appl Phys Lett...

Ngày tải lên: 21/06/2014, 17:20

... STEM measurement SZ, TH, and GH conducted the MBE growth JH, WW, and CH coordinated the study WL provided the idea and conceived the study together with ZL All authors read and approved the final ... 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 ... type-II GaSb/GaAs quantum dots Appl Phys Lett 1995, 67:656 10 Alonso-Álvarez D, Alén B, García JM, Ripalda JM: Optical investigation of type II GaSb/GaAs self-assembled quantum dots Appl Phys Lett...

Ngày tải lên: 22/06/2014, 00:20

... multifunctional nanoparticles composed of iron oxide nanoparticles and CdTe nanocrystals indicated QDs can be assembled on the silica surface by amino group, and Liu et al [20] have modified the surface of silica ... the formed core–shell nanoparticles were collected by centrifugation and the silica coated iron oxide nanoparticles were denoted as FS nanoparticles The surfaces of FS nanoparticles were modified ... the CdTe nanoparticles and the final multifunctional material As shown in Fig 5a, the CdTe nanoparticles were presented as red dots Figure 5b indicated the FSCS nanoparticles were also red dots, ...

Ngày tải lên: 22/06/2014, 00:20

... for hollow silica materials Herein, we present an advance in a simple and scalable wet chemical and subsequent annealing treatment synthesis of ultrafine hollow silica NPs (ca 24 nm) and magnetic ... external magnetic field and enhance the wear and corrosion resistance of the magnetic NPs [12] From this viewpoint, composite structures based upon nanometersized iron oxide and silica also have a ... bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates and tetraethoxysilane (TEOS) as silica source and then annealed in air For obtaining the ultrafine magnetic hollow silica NPs, we added hollow magnetite NPs...

Ngày tải lên: 22/06/2014, 00:20

... InAs QD with the height and base ˚ being 80 and 168 A, respectively, and lense-shaped InAs ˚ QD with the height and diameter being 80 and 240 A, respectively The distribution and value of strain ... self-assembled dots: an eight-band study, Phys Rev B 56, 4696 (1997) 16 O Stier, M Grundmann, D Bimberg, Electronic and optical properties of strained quantum dots modeled by 8-band kÁp theory, ... strain eH and the biaxial strain eB are defined as eH ðrÞ ¼ exx ðrÞ þ eyy ðrÞ þ ezz ðrÞ ð3Þ eB ðrÞ ¼ exx ðrÞ þ eyy ðrÞ À 2ezz ðrÞ VHH and VLH are the heavy-hole and light-hole bands, ac, av and b...

Ngày tải lên: 22/06/2014, 01:20

... mother liquor and (b) PHPP-SMNPs Fig UV spectra of (a) PHPP, (b) PHPP mixed with SMNPs, (c) PHPP dissolved in HCl and ethanol, (d) SMNPs dissolved in HCl and ethanol, and (e) SMNPs and PHPP dissolved ... significance Results and Discussion Preparation of Fe3O4 Nanoparticles Fe3O4 nanoparticles, prepared by co-precipitation method [19, 20], were 10 ± nm in diameter by measuring 200 randomly selected ... morphology (Fig 1a) and the characteristic peaks (Fig 1b), which was compatible with the values of standard pattern In addition to the dispersed and well-separated features, the formed Fe3O4 nanoparticles...

Ngày tải lên: 22/06/2014, 01:20

... states, E1,2 and E2,3 We found E1,2 = 21 meV and E2,3 = 16 meV for core QDs and E1,2 = 21 meV and E2,3 = 13 meV for core/shell QDs The PL time decay for core and core/shell samples (shown in Fig.1B) ... transitions |1i and |2i to carrier recombination from ± 1U and ± 1L states and the transition |3i to a surface states emission By analysing the temperature dependence of the PL intensities I1, I2 and I3 ... the PL of CdSe core and CdSe/ZnS core/shell QDs in the first ns arises from the intrinsic bright ± 1U and ± 1L states with lifetime of about 60 ps and 450 ps, respectively, and from surface states...

Ngày tải lên: 22/06/2014, 18:20