A growth method for inhibiting wedging of organic dast crystals

Abstract

The invention belongs to the technical field of crystal growth and relates to a growing method capable of inhibiting wedging of organic DAST crystals. Dried molecular sieves are put into a methanol solvent, methanol is obtained, a DAST raw material is mixed with methanol and dissolved, suction filtration is performed, a DAST-methanol growth solution is obtained and poured into a crystal growing tank after being subjected to thermal treatment, the temperature of the DAST-methanol growth solution in the crystal growing tank is stabilized above the equilibrium temperature, and a motor is started and stirs a water bath along with a stirrer synchronously; one end of each seed crystal is fixed at the bottom end of a seed crystal holder, the seed crystal holder is put into the DAST-methanol growth solution in a nitrogen atmosphere, the temperature of the DAST-methanol growth solution is reduced, the crystals are taken out after 20-50 days, and the DAST crystals with unwedged surfaces are obtained. The growth method is simple, the adopted growth device is simple in structure and convenient to operate, the purity of the growth solution can be improved, the stability of the growth solution is guaranteed, wedging of the crystals is effectively inhibited in the growing process, and the success rate of the high-quality growing crystals is high.

Description

Technical field: [0001] The invention belongs to the technical field of crystal growth, and relates to a solution cooling growth method for nonlinear optical crystals, in particular to a growth method for suppressing wedging of organic DAST crystals. Through the special design of the growth device and the further optimization of the growth process, the The wedging phenomenon that is easy to occur during the crystal growth process improves the crystal quality and ensures the growth of DAST single crystals with regular shapes and high quality. Background technique: [0002] Terahertz waves (0.1-10THz electromagnetic waves) have the advantages of low photon energy, high frequency, and good spatial resolution, and can be widely used in spectroscopy imaging, nondestructive testing, security inspection, quality control, high-precision confidential radar, and satellite-to-satellite broadband communication and other fields. Studies have shown that organic nonlinear optical crystal ...

AI Technical Summary

Problems solved by technology

At present, from the perspective of crystals, the research on the key growth process of DAST crystals in the world is still not mature enough, and it is difficult to obtain large-sized, especially high-quality crystals stably, which limits the application progress of DAST crystals in related fields

During the crystal growth process, affected by the surrounding environment and process conditions such as impurities in the solution, supersaturation of the solution, growth temperature gradient, and pH value, it is easy to cause the crystal to appear wedged, that is, certain directions of the crystal are constantly changing. Small, the crystal plane is bent, resulting in defects on the outer surface and inside of the crystal, which affects the use value of the crystal

Some scholars in Taiwan used the seed crystal method to grow larger-sized DAST crystals in a dual-temperature zone environment, but microcrystals appeared on the crystal surface, which destroyed the stability of the growth solution and reduced the crystal quality (A.S.Haja Hameed, W.C.Yu, Z.B. Chen, C.Y.Tai, C.W.Lan, Aninvestigation on the growth and characterization of DAST crystals grown by two zone growth technique, Journal of Crystal Growth, 282(2005) 117-124); Swiss scholars also grew larger-sized crystals by using the seed crystal method DAST crystals, but during the growth process, the crystal face appears wedged phenomenon, the surface is uneven, and the crystal quality is difficult to guarantee (B.Ruiz, M.Jazbinsek, P.Günter, Crystal growth of DAST, Crystal Growth & Design, 8 (11) ( 2008) 4173-4184), in order to grow high-quality DAST crystals, in addition to requiring no inclusions inside the crystal, the integrity of the appearance must also be good, that is, the crystal cannot be wedged, and the crystal surface must be smooth and flat

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