Hybrids consisting of CdSe/ZnS quantum dot (QD) as a core and thiol-group functionalized poly(3-hexylthiophene) (P3HT) as a shell were fabricated using the ligand-exchange method. We clearly observed the photovoltaic characteristics of a single QD-P3HT hybrid by using conducting atomic force microscopy. Monochromatic power conversion efficiency drastically increased with an increase in the molecular weight (Mw) of P3HT, suggesting sufficient photoinduced charge transfer between the QD and highly ordered P3HT chains. The nanoscale photoluminescence (PL) intensity for a single QD considerably decreased with increasing Mw of P3HT owing to charge transfer effects. On the basis of time-resolved PL and transient absorption spectra measurements of the QD-P3HT hybrids, we deduced that the exciton lifetimes of the QD were reduced with higher-Mw P3HT hybrids, and photobleaching was observed. The measured nanoscale optical characteristics of the single QD-P3HT hybrids support their distinct photovoltaic behaviors.
Bibliographical noteFunding Information:
This work was supported by a National Research Foundation (NRF) grant funded by the Korean government (MEST) (No. 2012R1A2A2A01045102 ). K.-S. Lee and S.Y. Kim acknowledge funding for this work from the NRF through the Active Polymer Center for Patterned Integration ( ERC R11-2007-050-01002-0 ).
© 2014 Elsevier B.V. All rights reserved.
- Quantum dot Optoelectronics
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Materials Chemistry
- Electrical and Electronic Engineering