Enhancement of nonlinear optical activity in new six-branched dendritic dipolar chromophore

Abstract

A new six-branched chromophore GGQ1 is designed and synthesized via the incorporation of an FTC-type chromophore 1 with phenyl glycerol ester. The six-branched chromophore GGQ1 shows a large molecular weight of 3834 Daltons and can directly form thin films with quite high active chromophore loading density. For comparison, guest–host doped polymer films are fabricated by doping chromophore 1 and BF1 into poly(4-vinylphenol). All of these doped films show a saturated trend in second harmonic generation coefficient (d₃₃) and a maximum d₃₃ value between 50–70 pm V⁻¹ around the doping concentration of 25 wt%, due to the strong interchromophore electrostatic interactions. In contrast, GGQ1 films display a d₃₃ value of 192 pm V⁻¹. The results indicate that the six-branched chromophore could efficiently reduce the interchromophore electrostatic interactions and enhance the macroscopic optical nonlinearity, showing promise for applications in nonlinear optical (NLO) materials.