Synthesis, crystal structure and third-order nonlinear optical properties in the near-IR range of a novel stilbazolium dye substituted with flexible polyether chains

A novel stilbazolium salt with flexible chains, trans- [4-[N,N-bis(2-(2-methoxyethoxy)ethyl)amino]styryl]-N-methylpyridinium tetraphenylborate, was designed, synthesized and fully characterized. Third-order nonlinear optical properties for the new stilbazolium salt have been explored. The results show that the novel dye possesses very large values of the real part of the cubic hyperpolarizability χ(3), up to 10−12 esu, and displays maximum two-photon absorption cross sections within the narrow wavelength range from 950 to 960 nm, while out of the range, it shows a large real part of χ(3), which was determined by two-photon induced fluorescence and open/closed aperture Z-scan measurements using femtosecond pulse laser in near-infrared range, respectively.

► A novel stilbazolium salt was designed and confirmed by crystallography. ► The molecular geometry optimization for calculation results from the crystal data. ► The photophysical properties were systematically investigated. ► The dye exhibits large two-photon absorption in narrow near-infrared range. ► It possesses large values of the real part of the cubic hyperpolarizability χ(3).