Nonlinear optical transmission properties of C60 dyads consisting of a light-harvesting diphenylaminofluorene antenna

Abstract

Highly enhanced nonlinear absorption cross section values of C 60(>DPAF-C2M), C60(>DPAF-C9), and C60(>DPAF-C10) dyads were detected up to 5400, 9700, and 14000 GM, respectively, in the 2.0 ps region in toluene at the concentration of 1.5 × 10-3 M. They were correlated to a trend showing higher efficiency in light transmittance attenuation down to 39-46% for the dyads C60(>DPAF-C10) and C60DPAF-C 9) with the increase of irradiance intensity up only to 140 GW/cm2. The phenomena were attributed to additional enhancement on the excited-state absorption of 1C60*(>DPAF- Cn) in the subpicosecond to picosecond region over the two-photon absorption of C60(>DPAF-Cn) in the femtosecond region. Its accumulative 2.0 ps absorption cross sections were estimated to be 8900 GM for 1C60*(>DPAF-C9), roughly one order of magnitude higher than its intrinsic femtosecond 2PA cross sections. © 2008 American Chemical Society.