Shape, Size, and Assembly Control of PbTe Nanocrystals

Department of Chemistry, University of California, Berkeley, CA 94720, USA.
Journal of the American Chemical Society (Impact Factor: 12.11). 09/2007; 129(32):9864-5. DOI: 10.1021/ja074145i
Source: PubMed


In this communication, we demonstrate an approach for shape control of PbTe nanocrystals. We succeeded in synthesizing three different shapes of PbTe nanoparticles, including cubes, cuboctahedra, and octahedra. These morphologies were prepared by changing the molar ratio between the Pb and Te precursors and also by changing the surfactant. Langmuir-Blodgett films were prepared using these PbTe nanocrystals.

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    • "As lead telluride, PbTe, has been the subject of particular attention as a thermoelectric material due to its high Z T [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13], many efforts have been made to improve thermoelectric properties of PbTe and its alloys, and thus increase the thermoelectric conversion efficiency. The thermoelectric efficiency is given by Z T = S 2 σ T /κ (S is thermopower, σ is electrical conductivity, κ is thermal conductivity and T is temperature), and S, σ and κ are not mutually exclusive. "
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    ABSTRACT: We report the thermoelectric performance of individual PbTe nanowires with sizes ranging from 76 to 436 nm grown from a vapor transport method that synthesizes high-quality, single-crystalline PbTe nanowires. Independent measurements of temperature-dependent Seebeck coefficient (S), thermal conductivity (κ) and electrical conductivity (σ) of individual PbTe nanowires were investigated. By varying the nanowire size, the simultaneous increase and decrease of S (-130 µV K(-1)) and κ (1.2 W m(-1) K(-1)), respectively, are achieved at room temperature. Our results demonstrate the enhanced thermoelectric properties of individual single-crystalline PbTe nanowires, compared to that of bulk PbTe, and can provide guidelines for future work on nanostructured thermoelectrics based on PbTe.
    Nanotechnology 07/2011; 22(29):295707. DOI:10.1088/0957-4484/22/29/295707 · 3.82 Impact Factor
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    ABSTRACT: In this contribution, a nucleation and growth mechanism of PbSe and PbTe nanoparticles are proposed. The formation and growth of PbSe and PbTe nanoparticles during their reaction synthesis were studied and followed using transmission electron microscopy, and their related techniques. In the synthesis method, trioctylphosphine-selenide and telluride were used as the chalcogen precursors, while lead oleate was employed as the lead precursor. Different synthesis conditions were tested to assess the effect of varying the reaction time, lead to chalcogen ratio, reaction temperature, and lead oleate concentration. The synthesized nanoparticles were characterized by means of electron diffraction, energy dispersive X-ray spectroscopy, scanning transmission electron microscopy, and electron energy loss spectroscopy, to obtain information related to their morphology, crystal structure, and composition. The experimental results suggest that the growth of the lead chalcogenide nanoparticles greatly relies on the reduction of Pb2+ ions to Pb0 atoms at early reaction times; this reduction of the lead precursor is evidenced by the formation of Pb nanoparticles with sizes between 1 and 3 nm under certain synthesis conditions. These Pb nanoparticles gradually disappear as the reaction progresses, suggesting that the reduced Pb0 atoms are able to contribute to the growth of the PbSe and PbTe nanoparticles, reaching sizes between 8 and 18 nm. The current results contribute to a better understanding of the nucleation and growth mechanisms of lead chalcogenide nanoparticles, which will enable the definition of more efficient synthesis routes of these types of nanostructures.
    Journal of Nanoparticle Research 05/2013; 15(5). DOI:10.1007/s11051-013-1620-7 · 2.18 Impact Factor
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