Chem. J. Chinese Universities ›› 2010, Vol. 31 ›› Issue (11): 2268.

• Articles • Previous Articles     Next Articles

Broadband Multiphoton Upconversion Fluorescence of Novel Dendrimers by a Femtosecond Ti∶Sapphire Laser

QIAN Ying1*, HU Kai-Ming1, ZHOU Zhi-Qiang2, LÜ Chang-Gui2, CUI Yi-Ping2   

  1. 1. School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China;
    2. Advanced Photonics Center, Southeast University, Nanjing 210096, China
  • Received:2009-12-31 Online:2010-11-10 Published:2010-11-10
  • Contact: QIAN Ying. E-mail: yingqian@seu.edu.cn
  • Supported by:

    国家自然科学基金(批准号: 60678042, 60877024)和东南大学科学基金(批准号: 9207041399)资助.

Abstract: The multiphoton absorption and multi-photon-excited upconversion fluorescence of dendrimers, 1,2,4,5-tetra(4-N,N-diphenylaminostyryl)benzene(TPAB), 1,2,4,5-tetra[4-N,N-di(4-bromophenyl)aminostyryl]benzene(TPAB-Br) and 1,2,4,5-tetra{4-{N,N-bis{4-{4-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]styryl}phenyl}amino styryl}benzene(TPAB-OXA), were measured by a femtosecond Ti∶sapphire laser. The absorption, fluorescence emission and fluorescence lifetime of these octupolar chromophores were investigated. Pumped by a femtosecond laser at 1300 nm and 800 nm, strong upconversion fluorescence were observed. The maximum peaks of two-photon fluorescence in the solution of CH2Cl2 are at 569 nm for TPAB, at 535 nm for TPAB-Br and at 621 nm for TPAB-OXA, respectively. The three-photon excited fluorescence with the central wavelength at 566 nm for TPAB, at 534 nm for TPAB-Br and at 610 nm for TPAB-OXA in the solution of CH2Cl2 were observed. The two-photon absorption cross-section of chromophores obtained by nonlinear transmission method was 61.86×10-50 cm4\5s/photon for TPAB and 65.98×10-50 cm4\5s/photon for TPAB-OXA in the solution of THF. Large optical power limiting was demonstrated for the octupolar chromophores. Their three-photon absorption coefficients of 1300 nm in THF were 3.88×10-79, 7.76×10-79 and 27.17×10-79 cm6\5s2, respectively. The dendrimers displayed large multi-photon absorption and strong upconversion fluorescence properties.

Key words: Dendrimer, Multiphoton absorption, Three-photon excited fluorescence, Two-photon excited fluorescence

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