Efficiently Site-Isolated Two-Photon Absorbing Dendrimer with Stilbazolium Chromophore

Abstract

To prevent the chromophore aggregation, a dendritic stilbazolium salt-type chromophore was synthesized via base-catalyzed coupling reaction of trihydroxy-functionalized tetraphenylborate stilbazolium salt core with appropriate peripheral Fréchet-type dendrons G3-benzyl bromide. The casted solid film of the resulting two-photon absorbing dendrimer showed high fIuorescence efficiency and optical power limiting activity which were not observed from the bare chromophore without dendrons. This result is attributed to the site isolation effect of its dendritic structure. By introducing this chromophore we have successfully fabricated micropatterns with high resolution by two-photon polymerization.

Keywords:

• dendrimer
• micropatterns
• optical power limiting
• photopolymerization
• stilbazolium salt
• two-photon absorption

Acknowledgments

This work was supported by the STAR program of Korea Foundation for International Cooperation of Science and Technology, Center for Advanced Functional Polymers from the Korea Science & Engineering Foundation, and the Asian Office of Aerospace Research and Development, USA. The authors acknowledge the help of Prof. H.-B. Sun and Prof. M. Cha for performing part of the measurements.