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.