Electronic and magnetic properties of Ni nanoparticles embedded in various organic semiconductor matrices

Björn Bräuer, Yana Vaynzof, Wei Zhao, Antoine Kahn, Wen Li, Dietrich R.T. Zahn, César De Julián Fernández, Claudio Sangregorio, Georgeta Salvan

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Ni nanoparticles with a size distribution from 2 to 6 nm, embedded in various organic matrices, were fabricated in ultrahigh vacuum. For this purpose metal free and Ni phthalocyanine, fullerene C60, and pentacene were coevaporated with Ni. When coevaporated, Ni and H2Pc react, leading to the formation of NiPc and Ni nanoparticles. The molecular structure of the matrix was found to have negligible effect on the size of the nanoparticles but to influence the magnetic anisotropy of the nanoparticles: Ni nanoparticles formed in the buckyball matrix have a cubic symmetry, while nanoparticles formed in matrices consisting of planar molecules exhibit a uniaxial symmetry. After exposure to atmosphere, photoelectron spectroscopy investigations demonstrate the presence of metallic Ni nanoparticles accompanied by Ni oxide and the existence of a charge transfer from the organic matrix to the particles in all investigated systems. The oxidized Ni nanoparticles exhibit a larger magnetic anisotropy compared to the freshly prepared particles which show superparamagnetic properties above 17 K. Moreover, photoelectron spectroscopy was used to probe the oxidation process of the Ni nanoparticles in different organic matrices. It could thus be shown that a matrix consisting of spherical molecules like C60 prevent the particles much better from oxidation compared to matrices of flat molecules.

Original languageEnglish (US)
Pages (from-to)4565-4570
Number of pages6
JournalJournal of Physical Chemistry B
Volume113
Issue number14
DOIs
StatePublished - Apr 9 2009

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Electronic and magnetic properties of Ni nanoparticles embedded in various organic semiconductor matrices'. Together they form a unique fingerprint.

  • Cite this

    Bräuer, B., Vaynzof, Y., Zhao, W., Kahn, A., Li, W., Zahn, D. R. T., De Julián Fernández, C., Sangregorio, C., & Salvan, G. (2009). Electronic and magnetic properties of Ni nanoparticles embedded in various organic semiconductor matrices. Journal of Physical Chemistry B, 113(14), 4565-4570. https://doi.org/10.1021/jp809777z