Abstract:

Three chalcone derivatives with tri-thiophene groups， 1-（α-tri-thiophene-2-yl）-3-（2， 4-dichlo-rophenyl） acry lone （a）， 1-（2， 5-dichlorophenyl）-3-（α-tri-thiophene-2-yl） acrylone （b） and 1-（3， 4-dich-lorophenyl）-3-（α-tri-thiophene-2-yl） acrylone （c） were synthesized by Claisen-Schmidt condensation reaction using α-tri-thiophene formaldehyde and three dichloroacetophenone as raw materials. The structures of derivatives were characterized by ¹H NMR and ¹³C NMR spectroscopy and LC-MS. Their nonlinear optical absorption properties were investigated by using Z-scan technique （600 nm， 180 fs）. Their polarizability， first hyperpolarizability， oscillator strength， transition energy， difference of dipole moment between ground state and excited state， main compositions of crucial transition state and the gap between HOMO and LUMO of a－c were calculated by time-dependent density functional theory approach. At the same time， their linear optical properties were measured. The results indicate that the derivative c has the highest ultraviolet absorption wavelength and fluorescence emission wavelength， best thermal stability and the highest polarizability. The intramolecular charge transfer can occur within three compounds a， b and c. Also， the nonlinear absorption is two-photon absorption， and both a and b show fifth-order nonlinear absorption. They exhibit ultrafast third-order nonlinear optical response， indicating that they are excellent candidate materials for nonlinear optics research.

Key words: Tri-thiophenyl chalcone derivatives, Z-scan technology, Theoretical calculation, Ultrafast nonlinear optical response