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

Abstract

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 CH2Cl2. 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 cm4·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. © 2009 Chinese Optics Letters.