Synthesis of Dual NIR Two-photon Absorptive [60]fullerenyl Multiadducts for Nonlinear Light-transmittance Reduction Application.

摘要

Synthesis of several C(sub 60-)(antenna)x conjugates was performed to demonstrate high flexibility in the design of organic nonlinear optical (NLO) nanostructures showing broadband characteristics with capability to absorb light over a wide range of wavelengths. It was achieved by covalent attachment of a hybrid combination of two types of light-harvesting fluorescent antenna chromophores on a C(sub 60) cage. Ultrafast photoresponsive intramolecular Foester resonance energy transfer among antenna units and shared excited energy-accepting C(sub 60) cage is proposed as a plausible mechanism to enhance the broadband NLO ability. Characterization of the branched triad C(sub 60)(>DPAF-C(sub 18))(> CPAF-C(sub 2M)) and the tetrad C(sub 60)(>DPAF-C(sub 18))(> CPAF-C(sub 2M))2 was carried out by various spectroscopic techniques. These compounds showed approximately equal extinction coefficients of optical absorption over 400-550 nm that corresponds to near-IR two-photon based excitation wavelengths at 780-1100 nm. These nanomaterials may be utilized in NLO coatings for achieving efficient light-transmittance reduction at the same NIR wavelengths.