Synthesis and crystal growth of 2, 3-dimethyl-N-[2-(hydroxy) benzylidene] aniline: An organic second-order non-linear optical crystal for non-linear optical (NLO) applications

Optically transparent organic single crystal of 2,3-Dimethyl-N-[2-(hydroxy) benzylidene] aniline (DHBA) has been successfully prepared, and the single crystals were grown with dimensions up to 10 x 5 x 2 mm(3) by using slow evaporation solution growth method in methanol. Single crystal X-ray diffraction (SCXRD) study revealed that the DHBA was crystallized in an orthorhombic crystal structure with P212121 space group, which is a crucial parameter for the second harmonic generation. The existence of various functional groups in the DHBA molecular structure was characterized by FT-IR, FT-Raman, and H-1 NMR techniques. UV-Vis-NIR absorption study reveals that the lower cut-off wavelength at 464 nm with transparency over the Vis-NIR spectral regions. The photoluminescence (PL) spectra of DHBA crystal exhibit a green emission centered at 538 nm. The thermal stability and melting temperature of DHBA was assessed by TG/DTA analysis. Vickers microhardness studies have also been investigated to check the mechanical stability of the grown crystal. The dielectric properties of DHBA have been tested in various frequency ranges from 50Hz to 5 MHz at three different temperatures (308K, 323K, and 348K), and the results are discussed. The second order NLO efficiency of the powdered DHBA crystal is three times greater than that of KDP. All of these results imply that DHBA crystal could be a desirable candidate for non-linear optical applications.

Automated summary

An optically transparent organic single crystal of 2,3-Dimethyl-N-[2-(hydroxy) benzylidene] aniline (DHBA) was successfully prepared using slow evaporation solution growth method in methanol with dimensions up to 10 x 5 x 2 mm(3). Various analytical techniques revealed the crystal structure, functional groups, optical properties, and non-linear optical efficiency of DHBA, suggesting its potential for non-linear optical applications.