Regensburg 2004 – wissenschaftliches Programm

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SYOH: Organic and Hybrid Systems for Future Electronics

SYOH 5: Poster

SYOH 5.10: Poster

Donnerstag, 11. März 2004, 18:00–21:00, B

Blinking and Emission Quenching of CdSe Nanocrystals in Organic Environments — •Thomas Blaudeck¹, Abey Issac², Frank Cichos¹, Edward Zenkevich³, Alexander Shulga³, and Christian von Borczyskowski² — ¹Institut für Physik 123705, TU Chemnitz, 09107 Chemnitz — ²Institut für Physik 121501, TU Chemnitz, 09107 Chemnitz — ³Institute of Molecular and Atomic Physics and B.I. Stepanov Institute of Physics National Academy of Sciences, 70 F. Skaryna Avenue, 220072 Minsk, Belarus

The interaction of ZnS capped CdSe nanocrystals with their environment is studied on an ensemble and single nanocrystal (NC) level. Individual CdSe NC’s show an emission intermittency (blinking), which is commonly related to an NC photo-ionization by electron tunneling. The statistics of this blinking is found to be independent of the studied NC even though NCs may differ in size and local structure of the surrounding polymer matrix. We analyze the obtained blinking statistics in terms of charge diffusion through trap states in the NCs vicinity and further compare this to current blinking model. Despite the insensitivity of the blinking process to the surrounding polymer matrix a strong interaction between CdSe NCs and pyridyl containing porphyrin molecules is found. The porphyrin molecules self-organize on the NC surface by ligation effects. The interaction of porphyrin and NC introduces a fast non-radiative decay of the NC emission, which is ascribed to an electron transfer process by electron tunneling. The dependence of this tunneling process on the NC size is discussed.