Structural Design, Growth And Properties Of Organic Nonlinear Optical Crystal EBST And Its Derivative

Organic nonlinear optical materials are widely used in optical information processing,high-speed electro-optic modulation,integrated optics,terahertz technology,and functional photonic construction.Therefore,researchers are committed to the design and exploration of high-efficiency organic nonlinear optical crystals to promote the vigorous development of the optoelectronics industry.The crystal growth process was improved,and the crystal growth was adopted natural evaporation method and slow cooling method in this paper.The EBST single crystal of 14×8×2 mm~3 was obtained.The EBST crystal structure was determined by single crystal XRD,and the first hyperpolarizabilityβmax,bond length change value,Hirshfeld surface,HOMO-LUMO orbital and ESP were calculated.The optical,electrical and thermal properties of EBST crystal were characterized.It is found that EBST crystal has a high SHG,which is 14 times that of the KDP crystal and 2.8 times that of the DAST crystal approximately,far exceeding most organic nonlinear optical crystals.Based on EBST crystal,a new type of quinoline crystal EBQ-T is successfully designed and synthesized by replacing the quinoline group with stronger electron ability on the D-π-A structure.Through single crystal X-ray diffraction,it was confirmed that the EBQ-T crystal belonged to the non-centrosymmetric structure,and the crystal structure was comprehensively analyzed combined with theoretical calculation.The crystal growth was adopted spontaneous nucleation method,and the single crystal of 11×5×2 mm~3 was obtained.A series of performance characterizations such as SHG,optical transmittance,energy band gap,luminescence characteristics,dielectric and thermal stability were carried out.A novel crystal of MBQ-T is synthesized based on the 2-methylquinoline acceptor.The SHG of MBQ-T is similar to DAST and about five times that of KDP crystal.Meanwhile,the properties of MBQ-T crystal were characterized and analyzed by UV-Vis-NIR,dielectric,TG/DSC and photoluminescence tests.