A Comprehensive Investigation on the Cooperative Branch Effect on the Optical Properties of Novel Conjugated Compounds

This paper presents a variety of conjugated derivatives with different number of arms (4-styryl-triphenylamine: C1, 4, 4'-di-styryltriphenylamine: C2, 4, 4', 4aEuro(3)-tri-styryltriphenylamine: C3). The linear absorption and fluorescence maxima and the molar extinction coefficients are in the order of C1 < C2 < C3 in various solvents. Two-photon absorption (TPA) up-converted emission of the derivatives were determined with Ti:sapphire femtosecond laser. The maximal TPA emission wavelength and the two-photon absorption cross section of the derivatives are also in the order of C1 < C2 < C3 in various solvents. The dipole moment changes of the derivatives between the excited state and the ground state were estimated from experiment, and they are in the order of C1 < C2 < C3, which is confirmed further by the molecular geometry optimization of the derivatives. The electron density distribution and the energy levels of the frontier orbital of the derivatives were analyzed. The cyclic voltammograms of the derivatives were performed and discussed.