Controlled Synthesis of Uniform Cobalt Phosphide Hyperbranched Nanocrystals Using Tri- n -octylphosphine Oxide as a Phosphorus Source

Type
Article

Authors
Zhang, Haitao
Ha, Don-Hyung
Hovden, Robert
Kourkoutis, Lena Fitting
Robinson, Richard D.

KAUST Grant Number
KUS-C1-018-02

Date
2011-01-12

Abstract
A new method to produce hyperbranched Co 2P nanocrystals that are uniform in size, shape, and symmetry was developed. In this reaction tri-n-octylphosphine oxide (TOPO) was used as both a solvent and a phosphorus source. The reaction exhibits a novel monomer-saturation-dependent tunability between Co metal nanoparticle (NP) and Co 2P NP products. The morphology of Co 2P can be controlled from sheaflike structures to hexagonal symmetric structures by varying the concentration of the surfactant. This unique product differs significantly from other reported hyperbranched nanocrystals in that the highly anisotropic shapes can be stabilized as the majority shape (>84%). This is the first known use of TOPO as a reagent as well as a coordinating background solvent in NP synthesis. © 2011 American Chemical Society.

Citation
Zhang H, Ha D-H, Hovden R, Kourkoutis LF, Robinson RD (2011) Controlled Synthesis of Uniform Cobalt Phosphide Hyperbranched Nanocrystals Using Tri- n -octylphosphine Oxide as a Phosphorus Source . Nano Lett 11: 188–197. Available: http://dx.doi.org/10.1021/nl103400a.

Acknowledgements
We thank John Grazul, Yuanming Zhang, and Mahmut Aksit for assistance with HRTEM, electron diffraction, and SEM, respectively. We also thank William Bassett for his help with cyclic twinning and mineralogy. L.F.K. is pleased to acknowledge helpful discussions with Peter Ercius. This work was supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). We also acknowledge support of Cornell Center for Materials Research (CCMR) with funding from the Materials Research Science and Engineering Center program of the National Science Foundation (cooperative agreement DMR 0520404), and support of Energy Materials Center at Cornell (EMC2), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science under Award Number DE-SC0001086.

Publisher
American Chemical Society (ACS)

Journal
Nano Letters

DOI
10.1021/nl103400a

PubMed ID
21141992

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