Table of Contents
International Journal of Spectroscopy
Volume 2012, Article ID 971791, 14 pages
Research Article

Size-Dependent Non-FRET Photoluminescence Quenching in Nanocomposites Based on Semiconductor Quantum Dots CdSe/ZnS and Functionalized Porphyrin Ligands

1National Technical University of Belarus, Nezavisimosti Avenue 65, 220013 Minsk, Belarus
2Institute for Print and Media Technology, University of Technology, 09107 Chemnitz, Germany
3Department of Science and Technology, Organic Electronics, Linköping University, Bredgatan 34, 60174 Linköping, Sweden
4Institute of Semiconductor Physics, Lavrentjev avenue 13, 630090 Novosibirsk, Russia
5Center for Nanostructured Materials and Analytics, Institute of Physics, Chemnitz University of Technology, Reichenhainer Street 70, 09107 Chemnitz, Germany

Received 28 March 2011; Accepted 14 June 2011

Academic Editor: Sandip Dhara

Copyright © 2012 Eduard I. Zenkevich et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We review recent experimental work to utilize the size dependence of the luminescence quenching of colloidal semiconductor quantum dots induced by functionalized porphyrin molecules attached to the surface to describe a photoluminescence (PL) quenching process which is different from usual models of charge transfer (CT) or Foerster resonant energy transfer (FRET). Steady-state and picosecond time-resolved measurements were carried out for nanocomposites based on colloidal CdSe/ZnS and CdSe quantum dots (QDs) of various sizes and surfacely attached tetra-mesopyridyl-substituted porphyrin molecules (“Quantum Dot-Porphyrin” nanocomposites), in toluene at 295 K. It was found that the major part of the observed strong quenching of QD PL in “QD-Porphyrin” nanocomposites can neither be assigned to FRET nor to photoinduced charge transfer between the QD and the chromophore. This PL quenching depends on QD size and shell and is stronger for smaller quantum dots: QD PL quenching rate constants 𝑘 𝑞 scale inversely with the QD diameter. Based on the comparison of experimental data and quantum mechanical calculations, it has been concluded that QD PL quenching in “QD-Porphyrin” nanocomposites can be understood in terms of a tunneling of the electron (of the excited electron-hole pair) followed by a (self-) localization of the electron or formation of trap states. The major contribution to PL quenching is found to be proportional to the calculated quantum-confined exciton wave function at the QD surface. Our findings highlight that single functionalized molecules can be considered as one of the probes for the complex interface physics and dynamics of colloidal semiconductor QD.