Third-order nonlinear optical property of non-identical three-branched molecules based on triphenylamine

A series of non-identical three-branched molecules with two D–π–D′ and one D–π–A branchs were synthesized based on triphenylamine as a core. Both the λmaxab and λmaxfl are red-shifted slightly with the strength of the peripherical acceptor reducing in these molecules. Their third-order nonlinear optical properties were measured by Z-scan technique with a Ti: Sapphire laser (2.5 ps, 76 MHz, 38 mW) at 800 nm in chloroform. All the six molecules display nonlinear refraction and nonlinear absorption response at this condition. The results indicate that both the nonlinear absorption and nonlinear refraction response increase with the strength of acceptor weakening in these molecules, and the Re(χ(3)) of these molecules are three orders of magnitude larger than their Im(χ(3)).