Synthesis, growth, structure analysis and performance characterization of DOST crystal: a nonlinear functional material with a wide range of applications

Abstract

Novel organic nonlinear optical crystals of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 3,4-dimethoxysulfonate (DOST) with high quality were grown by a spontaneous nucleation method. The crystal quality, defect types and growth mechanism were studied by a chemical etching method and synchrotron radiation X-ray topography. The non-centrosymmetric P2₁ space group of the crystal was confirmed by single-crystal XRD, and the HOMO–LUMO orbital diagram and molecular electrostatic potential (ESP) surface were drawn. Spectroscopy studies have shown that the DOST crystal has high optical transmittance (≥70%), a wide transmission range and an energy bandwidth of 2.43 eV. As a kind of nonlinear optical (NLO) material, the crystal has an extremely high second-order nonlinear effect. The second-harmonic generation (SHG) efficiency is about 4 times that of DAST, which exceeds the SHG efficiency of most second-order nonlinear materials that have been reported. The dielectric and ferroelectric properties of the DOST crystal under different temperature and frequency conditions are measured. In addition, it is proved by PL and TG-DSC tests that the DOST crystal also has green light emission characteristics and good thermal stability.