Aggregation-Enhanced Fluorescence and Two-Photon Absorption in Nanoaggregates of a 9,10-Bis[4′-(4″-aminostyryl)styryl]anthracene Derivative

Authors


  • This work was supported in part by a grant from the directorate of Chemistry and Life Science of the Air Force office of Scientific Research, in part by a grant from DMR, international program of the National Science Foundation, in part by the Post-doctoral Fellowship Program of Korea Science & Engineering Foundation (KOSEF), and in part by the Post-doctoral Fellowship Program of the Swedish Foundation for International Cooperation in Research and Higher Education (STINT). We thank Dr. Marek Samoc at Laser Physics Centre, Australian National University for helpful discussions. Supporting Information is available online from Wiley InterScience or from the author.

Abstract

This paper reports the design, synthesis, and theoretical modeling of two-photon properties of a new class of chromophore that exhibits enhanced two-photon absorption (TPA) and subsequently generated strong up-converted emission in nanoaggregate forms. This chromophore utilizes the basic structural unit of 9,10-bis[4′-(4″-aminostyryl)styryl]anthracene that exhibits large internal rotation in the monomer form in organic solvents, whereby the fluorescence is greatly reduced. In nanoaggregates formed in water, the internal rotation is considerably hindered, leading to significant increases of TPA and fluorescence quantum yield. Theoretical modeling of the conformational structure and dynamics has utilized a semiempirical pm3 formalism. The TPA cross sections of the monomer and the aggregate states have been calculated on the basis of the quadratic response theory applied to a single-determinant self-consistent field reference state making use of a split-valence 6-31G* basis set.

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