851
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Peng ZA, Peng X. Nearly monodisperse and shape-controlled CdSe nanocrystals via alternative routes: nucleation and growth. J Am Chem Soc 2002; 124:3343-53. [PMID: 11916419 DOI: 10.1021/ja0173167] [Citation(s) in RCA: 744] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nucleation and growth of colloidal CdSe nanocrystals with a variety of elongated shapes were explored in detail. The critical size nuclei for the system were magic sized nanoclusters, which possessed a sharp and dominated absorption peak at 349 nm. The formation of the unique magic sized nuclei in a broad monomer concentration range was not expected by the classic nucleation theory. We propose that this was a result of the extremely high chemical potential environment, that is, very high monomer concentrations in the solution, required for the growth of those elongated nanocrystals. The shape, size, and size/shape distributions of the resulting nanocrystals were all determined by two related factors, the magic sized nuclei and the concentration of the remaining monomers after the initial nucleation stage. Without any size sorting, nearly monodisperse CdSe quantum structures with different shapes were reproducibly synthesized by using the alternative cadmium precursors, cadmium-phosphonic acid complexes. A reasonably large excess of the cadmium precursor, which is less reactive than the Se precursor, was found beneficial for the system to reach the desired balance between nucleation and growth. The shape evolution and growth kinetics of these elongated nanocrystals were consistent with the diffusion-controlled model proposed previously. The branched nanocrystals had to grow at very high monomer concentrations because the multiple growth centers at the end of each branch must be fed with a very high diffusion flux to keep all branches in the 1D-growth mode. The rice-shaped nanocrystals were found as special products of the 3D-growth stage. The growth of the nanocrystals in the 1D-growth stage was proven to be not unidirectional after the length of the nanocrystals reached a certain threshold. Experimental results indicate that coordinating solvents and two ligands with distinguishable coordinating abilities are both not intrinsic requirements for the growth of elongated CdSe nanocrystals.
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Affiliation(s)
- Z Adam Peng
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
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852
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Qu L, Peng X. Control of photoluminescence properties of CdSe nanocrystals in growth. J Am Chem Soc 2002; 124:2049-55. [PMID: 11866620 DOI: 10.1021/ja017002j] [Citation(s) in RCA: 768] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photoluminescence (PL) quantum yield (QY) of CdSe nanocrystals during their growth under a given set of initial conditions increases monotonically to a certain maximum value and then decreases gradually. Such a maximum is denoted as a PL "bright point", which does not always overlap with the minimum point of the PL peak width for the same reaction. The experimental results suggest that the existence of the PL bright point is a general phenomenon during the growth of semiconductor nanocrystals and likely is a signature of an optimal surface structure/reconstruction of the nanocrystals grown under a given set of initial conditions. The position of the bright point, the highest PL QY, the types of the bright points (sharp or flat), the sharpness of the PL peak, etc., were all strongly dependent on the initial Cd:Se ratio of the precursors in the solution. A large excess of the selenium precursor, with 5-10 times more selenium precursor than the amount of the cadmium precursor, was found necessary to achieve a high PL QY value and a narrow emission profile. The existence of the PL bright point and the sensitive temporal variation of the PL QY during the growth of semiconductor nanocrystals can explain the unpredictable nature and poor reproducibility of the PL properties of the as-prepared semiconductor nanocrystals observed previously. Furthermore, the knowledge gained in this study enabled us to reproducibly synthesize highly luminescent CdSe nanocrystals through a relatively simple and safe synthetic scheme. In a traditionally weak emission window for CdSe nanocrystals, the orange-red optical window, the PL QY of the as-prepared CdSe nanocrystals reached as high as 85% at room temperature, and the full width at half-maximum of the corresponding PL peak was as narrow as 23 nm, about 65-80 meV depending on the emitting position. The PL properties of the as-prepared CdSe nanocrystals are stable upon aging for at least several months. These as-prepared nanocrystals represent a series of best emitters that are highly efficient, highly pure in emission color, stable, and continuously tunable by simply varying the size of the nanocrystals.
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Affiliation(s)
- Lianhua Qu
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA
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853
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Burda C, Link S, Mohamed MB, El-Sayed M. The pump power dependence of the femtosecond relaxation of CdSe nanoparticles observed in the spectral range from visible to infrared. J Chem Phys 2002. [DOI: 10.1063/1.1446851] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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854
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Urban JJ, Yun WS, Gu Q, Park H. Synthesis of single-crystalline perovskite nanorods composed of barium titanate and strontium titanate. J Am Chem Soc 2002; 124:1186-7. [PMID: 11841284 DOI: 10.1021/ja017694b] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the solution-based synthesis of single-crystalline nanorods composed of barium titanate (BaTiO3) and strontium titanate (SrTiO3), which yields well-isolated nanorods with diameters ranging from 5 to 60 nm and lengths reaching up to >10 mum. Electron microscopy and diffraction measurements show that these nanorods are composed of single-crystalline cubic perovskite BaTiO3 and SrTiO3 with a principal axis of the unit cell preferentially aligned along the wire length. These BaTiO3 and SrTiO3 nanorods should provide promising materials for fundamental investigations on nanoscale ferroelectricity, piezoelectricity, and paraelectricity.
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Affiliation(s)
- Jeffrey J Urban
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
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855
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Hu J, Wang, Li LS, Yang W, Alivisatos AP. Semiempirical Pseudopotential Calculation of Electronic States of CdSe Quantum Rods. J Phys Chem B 2002. [DOI: 10.1021/jp013204q] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiangtao Hu
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, Materials Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, National Research Scientific Computing Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Wang
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, Materials Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, National Research Scientific Computing Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Liang-shi Li
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, Materials Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, National Research Scientific Computing Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Weidong Yang
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, Materials Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, National Research Scientific Computing Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - A. Paul Alivisatos
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, Materials Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, National Research Scientific Computing Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
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856
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857
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Jun YW, Jung YY, Cheon J. Architectural control of magnetic semiconductor nanocrystals. J Am Chem Soc 2002; 124:615-9. [PMID: 11804492 DOI: 10.1021/ja016887w] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Shape- and dopant-controlled magnetic semiconductor nanocrystals have been achieved by the thermolysis of nonpyrophoric and less reactive single molecular precursors under a monosurfactant system. Reaction parameters governing both the intrinsic crystalline phase and the growth regime (kinetic vs thermodynamic) are found to be important for the synthesis of various shapes of MnS nanocrystals that include cubes, spheres, 1-dimensional (1-D) monowires, and branched wires (bipods, tripods, and tetrapods). Obtained nanowires exhibit enhanced optical and magnetic properties compared to those of 0-D nanospheres. Proper choice of molecular precursors and kinetically driven low-temperature growth afford dopant controlled 1-D Cd1-xMn(x)S nanorods at high levels (up to approximately 12%) of Mn, which is supported by repeated surface exchange experiments and X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) analyses.
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Affiliation(s)
- Young-wook Jun
- Department of Chemistry and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology, Taejon 305-701, Korea
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858
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859
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Eilon MJ, Mokari T, Banin U. Surface Exchange Effect on Hyper Rayleigh Scattering in CdSe Nanocrystals. J Phys Chem B 2001. [DOI: 10.1021/jp012577o] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michal Jacobsohn Eilon
- Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University, Jerusalem 91904, Israel
| | - Taleb Mokari
- Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University, Jerusalem 91904, Israel
| | - Uri Banin
- Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University, Jerusalem 91904, Israel
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860
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Michalet X, Pinaud F, Lacoste TD, Dahan M, Bruchez MP, Alivisatos AP, Weiss S. Properties of Fluorescent Semiconductor Nanocrystals and their Application to Biological Labeling. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/1438-5171(200112)2:4<261::aid-simo261>3.0.co;2-p] [Citation(s) in RCA: 310] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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861
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Michalet X, Pinaud F, Lacoste TD, Dahan M, Bruchez MP, Alivisatos AP, Weiss S. Properties of Fluorescent Semiconductor Nanocrystals and their Application to Biological Labeling. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/1438-5171(200112)2:4%3c261::aid-simo261%3e3.0.co;2-p] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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862
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Kan S, Felner I, Banin U. Synthesis, characterization, and magnetic properties of α-MnS nanocrystals. Isr J Chem 2001. [DOI: 10.1560/1fb3-1pf4-72jq-0aqc] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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863
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Soulantica K, Maisonnat A, Senocq F, Fromen MC, Casanove MJ, Chaudret B. Selective Synthesis of Novel In and In3Sn Nanowires by an Organometallic Route at Room Temperature. Angew Chem Int Ed Engl 2001. [DOI: 10.1002/1521-3757(20010817)113:16<3071::aid-ange3071>3.0.co;2-q] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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864
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Rabani E. Structure and electrostatic properties of passivated CdSe nanocrystals. J Chem Phys 2001. [DOI: 10.1063/1.1380748] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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865
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Gerion D, Pinaud F, Williams SC, Parak WJ, Zanchet D, Weiss S, Alivisatos AP. Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots. J Phys Chem B 2001. [DOI: 10.1021/jp0105488] [Citation(s) in RCA: 1067] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniele Gerion
- Department of Chemistry, University of California, Berkeley, California 94720, and Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
| | - Fabien Pinaud
- Department of Chemistry, University of California, Berkeley, California 94720, and Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
| | - Shara C. Williams
- Department of Chemistry, University of California, Berkeley, California 94720, and Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
| | - Wolfgang J. Parak
- Department of Chemistry, University of California, Berkeley, California 94720, and Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
| | - Daniela Zanchet
- Department of Chemistry, University of California, Berkeley, California 94720, and Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
| | - Shimon Weiss
- Department of Chemistry, University of California, Berkeley, California 94720, and Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
| | - A. Paul Alivisatos
- Department of Chemistry, University of California, Berkeley, California 94720, and Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
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866
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Jun YW, Lee SM, Kang NJ, Cheon J. Controlled synthesis of multi-armed CdS nanorod architectures using monosurfactant system. J Am Chem Soc 2001; 123:5150-1. [PMID: 11457367 DOI: 10.1021/ja0157595] [Citation(s) in RCA: 495] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Y W Jun
- Department of Chemistry and School of Molecular Science BK21, Korea Advanced Institute of Science and Technology (KAIST), Taejon 305-701, Korea
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867
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Talapin DV, Rogach AL, Kornowski A, Haase M, Weller H. Highly Luminescent Monodisperse CdSe and CdSe/ZnS Nanocrystals Synthesized in a Hexadecylamine-Trioctylphosphine Oxide-Trioctylphospine Mixture. NANO LETTERS 2001; 1:207-211. [PMID: 35897166 DOI: 10.1021/nl0155126] [Citation(s) in RCA: 683] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Highly monodisperse CdSe nanocrystals were prepared in a three-component hexadecylamine-trioctylphosphine oxide-trioctylphosphine (HDA-TOPO-TOP) mixture. This modification of the conventional organometallic synthesis of CdSe nanocrystals in TOPO-TOP provides much better control over growth dynamics, resulting in the absence of defocusing of the particle size distribution during growth. The room-temperature quantum efficiency of the band edge luminescence of CdSe nanocrystals can be improved to 40-60% by surface passivation with inorganic (ZnS) or organic (alkylamines) shells.
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Affiliation(s)
- Dmitri V Talapin
- Institute of Physical Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Andrey L Rogach
- Institute of Physical Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Andreas Kornowski
- Institute of Physical Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Markus Haase
- Institute of Physical Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Horst Weller
- Institute of Physical Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
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