The important role of tetraphenylethene on designing bichromophores for organic nonlinear optical materials

Abstract

Organic electro-optical (OEO) materials still exist huge challenges to achieve these materials for practical use. In this work, a novel bichromophores Y was synthesized via esterification reaction with julolidine donor chromophores and systematically studied. Chromophore Y presented good solubility, excellent thermal stability, and also with great transparency. Besides, the hyperpolarizability (β) of this new chromophore was computed by density functional theory. To our suprise, in electro-optic activities, the doped film containing chromophore Y performed an extremely small electro-optic coefficient (r33) with 13 pm/V. This outcome indicated that the nonplanar molecular structures of the TPE1 moieties can weaken the electrostatic interactions between molecules, but the size of this chromophore is too big to be polarized, thus leading the macroscopic EO activity decreased sharply.