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Portrait of Tönu Pullerits; Photo: Kennet Ruona

Tönu Pullerits

Professor

Portrait of Tönu Pullerits; Photo: Kennet Ruona

An optical power limiting and ultrafast photophysics investigation of a series of multi-branched heavy atom substituted fluorene molecules

Author

  • Hampus Lundén
  • Delphine Pitrat
  • Jean Christophe Mulatier
  • Cyrille Monnereau
  • Iulia Minda
  • Adrien Liotta
  • Pavel Chábera
  • Didrik K. Hopen
  • Cesar Lopes
  • Stéphane Parola
  • Tönu Pullerits
  • Chantal Andraud
  • Mikael Lindgren

Summary, in English

A common molecular design paradigm for optical power limiting (OPL) applications is to introduce heavy atoms that promote intersystem crossing and triplet excited states. In order to investigate this effect, three multi-branched fluorene molecules were prepared where the central moiety was either an organic benzene unit, para-dibromobenzene, or a platinum(II)-alkynyl unit. All three molecules showed good nanosecond OPL performance in solution. However, only the dibromobenzene and Pt-alkynyl compounds showed strong microsecond triplet excited state absorption (ESA). To investigate the photophysical cause of the OPL, especially for the fully organic molecule, photokinetic measurements including ultrafast pump-probe spectroscopy were performed. At nanosecond timescales, the ESA of the organic molecule was larger than the two with intersystem crossing (ISC) promoters, explaining its good OPL performance. This points to a design strategy where the singlet-state ESA is balanced with the ISC rate to increase OPL performance at the beginning of a nanosecond pulse.

Department/s

  • Chemical Physics
  • NanoLund: Center for Nanoscience
  • eSSENCE: The e-Science Collaboration

Publishing year

2019

Language

English

Publication/Series

Inorganics

Volume

7

Issue

10

Document type

Journal article

Publisher

Multidisciplinary Digital Publishing Institute

Topic

  • Atom and Molecular Physics and Optics
  • Inorganic Chemistry

Keywords

  • Excited state absorption
  • Optical power limiting
  • Reverse saturable absorption
  • Ultra-fast pump-probe spectroscopy

Status

Published

ISBN/ISSN/Other

  • ISSN: 2304-6740