Inter- and intra-molecular energy transfers of encapsulated dyes in dendrimers

Akira Otomo, Minniu Zhou, Seiichi Furumi, Shiyoshi Yokoyama, Shinro Mashiko

Research output: Contribution to journalConference articlepeer-review

Abstract

Dendrimers are capable to encapsulate small molecules inside them. Because three-dimensional structures of dendrimers are highly controllable, energy transfers among dye molecules encapsulated inside them can be controlled precisely. Electronic energy transfers from optical excited molecules are categorized into two classes, Förster and Dexter types. Inter-molecular interactions between encapsulated dyes can be expressed as the Förster (singlet-singlet) energy transfer, because the size of dendrimers extends to a few nanometers. We have evaluated time resolved optical responses in rhodamine-cored dendrimer films. Fast decay in fluorescent lifetime is observed and it depends on the dendrimer size. A low generation dendrimer shows lifetime as short as 10 psec without severe quenching of fluorescence. A quadratic dependence of the emission intensity on density of molecules indicates that the origin of the short lifetime is not only energy transfer, but also super-radiance. Since the Dexter (triplet-triplet) energy transfer occurs in short range of 1.0 nm, we attached both donor and acceptor molecules to a dendrimer for investigation. We demonstrated photocrosslinking via triplet-triplet energy transfer from donor molecules encapsulated to acceptors attached at the surface. This procedure of triplet-triplet energy transfer in dendritic molecules opens up way to design novel optical and electrical molecular devices.

Original languageEnglish
Pages (from-to)37-43
Number of pages7
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume4798
DOIs
Publication statusPublished - Dec 1 2002
Externally publishedYes
EventLinear and Nonlinear Optics of Organic Materials II - Seattle, WA, United States
Duration: Jul 9 2002Jul 11 2002

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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