Linear and nonlinear optical properties of two novel D–π–A–π–D type conjugated oligomers with different donors

Experimental and theoretical studies on the donor-dependent optical characteristics of two D–π–A–π–D type linear fluorenone-based conjugated oligomers are presented, where fluorene and triphenylamine act as the donors, respectively. Because of the strong electron-donating ability, the triphenylamine chromophores lead to red-shifts of spectral features, shorten the excited state lifetime, and enhance the two-photon fluorescence efficiency and two-photon absorption cross-section in comparison with fluorene groups. Quantum chemical calculations provide complementary information regarding the molecular structures and the frontier orbitals, which can provide a deep insight into the electronic structure and properties of oligomers.

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► Donor-dependent optical properties of novel fluorenone-based oligomers are studied.
► Triphenylamine donor red-shifts the steady-state spectra compared to fluorene.
► Compared to fluorene donor, triphenylamine could increase the TPF efficiency.
► Triphenylamine donor could enhance the TPA cross-section compared to fluorene.
► Electronic structure and properties were learned by quantum chemical calculations.