Linear and nonlinear optical properties of triphenylamine-functionalized C₆₀: insights from theory and experiment

Abstract

In the present study we report on the linear and nonlinear optical properties of C60–triphenylamine (TPhA) hybrids. The synthesized materials were prepared following the 1,3-dipolar cycloaddition of azomethine ylides onto the skeleton of C60 forming the TPhA-based monoadduct, equatorial bis-adduct and dumbell C60. Complementary spectroscopic techniques, such as NMR, MALDI-TOF-MS, and ATR-IR are applied for the structural characterization of the hybrid materials, while intermolecular electronic interactions are investigated by UV-Vis measurements. In all considered cases, C60 serves as an acceptor while the triphenylamine unit is chosen as a donor. In order to investigate the dependence of the second-order hyperpolarizability on the architecture of the systems (D–A, A–D–A) we use a Z-scan technique employing 532 nm, 35 ps laser pulses. We have found that the total second-order hyperpolarizability of the C60–TphA–C60 system is several times larger than that of TPhA–C60. The results of experimental measurements are supported by quantum-chemical calculations.