Tailoring the chemical structures and nonliear optical properties of julolidinyl-based chromophores by molecular engineering

Abstract To study the impact of component on performance of the nonlinear (NLO) optical properties, a series of NLO chromophores contained julolidinyl groups as the electron donor, two kinds of pi-conjugated bridge (divinylisophorone, divinylthiophene), two kinds of electron acceptor (TCF (2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran) and CF3-Ph-TCF (2-dicyanomethylene-3-cyano-4,5-dimethyl-5-trifluoromethyl-2,5-dihydrofuran)) were synthesized and characterized. The microscopic nonlinear optical properties including solvent dependence of dipole moment (μ), hyperpolarizability (β), static polarizability (ɑ), and bond length alternation (BLA) of all chromophores were demonstrated by density functional theory (DFT) calculations. The macroscopic properties of EO effect were measured by simple reflection method, and the highest EO coefficient (r33) was 256 p.m./V. The solvatochromic behavior and thermal stability were also evaluated to study the structure-property relationships. This study explained the influence of microstructure on macroscopic performance in depth for the julolidinyl-based chromophores.