Electrochemical,thermal,and photophysical properties of novel two-photon absorption chromophores

Electrochemical,thermal,and photophysical properties of novel two-(BPODPA),four-(BBPOPA),and six-branch (TBPOA) triphenylamine chromophores are studied.The decomposition temperature of chromophores reaches 373-412°C.The electrochemical properties is explored by cyclic voltammetry.The ionization potential of chromophores is in the range of 5.14-5.18 eV.Excitation at 400 nm reveals emission peaks at 483-487 nm and the fluorescence quantum yields are 0.73-0.75 in CH 2 Cl 2.Two-photon absorption (TPA) properties of chromophores are measured by nonlinear transmission method.The maximum TPA cross-section values are measured at 758 nm to be 20369 GM (1 GM=10-50 cm 4 ·s/photon) for TBPOA,7024 GM for BBPOPA,and 1227 GM for BPODPA,respectively.When pumped with 800-nm laser irradiation,chromophores show strong two-photon excited blue-green fluorescence at 502-518 nm.These results provide a basis for understanding the electronic and optical properties of the conjugated multi-branch chromophore in terms of the underlying molecular and electronic structures.