Author: Eduard I. Zenkevich
Requested Type: Either Oral or Poster
Submitted: 2015-03-15 00:25:50
Co-authors: A.P. Stupak, C. Goehler, C. Krasselt, C. von Borczyskowski
National Technical University of Belarus
Prospect Nezavisimosti, 65
At the moment, the main obstacle on the path to the development of efficient quantum dot-based functional nanomaterials is our limited understanding of quantum dot (QD) surfaces, their interaction with capping ligands, and their impact on charge and energy transfer between QDs and attached dye molecules. Of special interest is an understanding on a one-molecule-to-one-QD base. A large variety of functionalized organic molecules are able to modify QD optical properties which may be controlled by temperature and related to surface reconstructions.
In a given paper, we report that dye molecules replace (a few) ligand molecules, which results in QD photoluminescence (PL) energy shifts of 10 – 20 meV and in an increased non-radiative PL relaxation depending on temperature. In this study, we combine ensemble and single QD data to solve several not yet well understood aspects of PL properties related to the heterogeneity of QD surfaces. The experimental findings lie in the scope of recent calculations on detailed QD surface properties and also provide new insights into the origin of PL blinking effects for QDs. Thus, increasing knowledge of specific interactions at the QD surface will allow for a guided tailoring of QDs for applications in photovoltaics and nanosensorics.