The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Default user image.

Oleg Mirzov

System architect

Default user image.

Single chain versus single aggregate spectroscopy of conjugated polymers. Where is the border?

Author

  • Hongzhen Lin
  • Ralph Hania
  • Robert Bloem
  • Oleg Mirzov
  • Daniel Thomsson
  • Ivan Scheblykin

Summary, in English

Single chains of conjugated polymers e.g. MEH-PPV (poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) have become interesting objects for single molecule spectroscopy (SMS) studies. However, most of the experiments so far were performed without full awareness of the isolation status of the polymer chains in host matrices. We used steady-state and time-resolved fluorescence methods and 2D polarization single molecule imaging technique to unravel the isolation/aggregation status of MEH-PPV in spin-coated films prepared at different conditions. It turned out that a sample showing isolated bright spots in fluorescence images could be obtained in a very broad concentration range of MEH-PPV when toluene was used as a solvent and PMMA as a matrix. If the MEH-PPV concentration was not sufficiently low, a substantial fraction of the fluorescence spots should be assigned to individual nano-aggregates rather than truly isolated chains of the polymer. Contrary to single aggregates, truly isolated MEH-PPV chains showed blue-shifted emission spectra, mono-exponential fluorescence decay dynamics with relatively long lifetimes (0.4-1.2 ns), and high polarization anisotropy. We argue that insufficient control of the concentration in the published SMS studies of MEH-PPV resulted in incorrect assigning of some spectroscopic properties of single aggregates to isolated MEH-PPV chains. We believe this to be the main origin of discrepancies among the published data in this field.

Department/s

  • Chemical Physics
  • NanoLund: Centre for Nanoscience

Publishing year

2010

Language

English

Pages

11770-11777

Publication/Series

Physical chemistry chemical physics : PCCP

Volume

12

Document type

Journal article

Publisher

Royal Society of Chemistry

Topic

  • Atom and Molecular Physics and Optics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1463-9084