Janus molecules: large second-order nonlinear optical performance, good temporal stability, excellent thermal stability and spherical structure with optimized dendrimer structure

In this paper, Janus molecules J1 and J2, based on the second-order nonlinear optical (NLO) chromophore of FTC (Fang's thermally stable chromophore), were designed and synthesized, in which the arrangement of chromophore moieties was different on the two sides of the core. Especially, in J2, each FTC piece had similar direction and a more similar spherical structure realized. Janus molecule J2 exhibited good thermal stability and excellent nonlinear optical performance. Thanks to the unique molecular topology, an ultrahigh d33 value of 529 pm V−1 at the wavelength of 1950 nm has been achieved, with 80% of its value retained at the high temperature of 161 °C. Coupled with the good thermal stability and very simple structure, the obtained results are valuable for the further development of NLO materials.