Rapid formation of imidazolium glutarate (IMGA) compound and investigation of its single crystal growth by modified vertical Bridgman technique for optical limiting applications

In this paper, we have examined the formation of the imidazole glutarate adduct by protonation-deprotonation between imidazole and glutaric acid using a direct precipitation method within a short period. Following that, we have succeeded in growing imidazolium glutarate (IMGA) single crystal directly from synthesized material and we have also grown IMGA single crystal from the melt method using the vertical Bridgman technique for the first time in literature. A special Bridgman furnace was constructed with a slight modification in the winding section for this crystal growth. Crystal structure, phase purity, and growth plane were analyzed for the grown crystal from both single and powder XRD analysis. Functional groups were verified after the growth using FTIR transmittance analysis. The optical homogeneity and growth mechanism were scrutinized by birefringence interferogram and chemical etching studies, respectively. The grown IMGA has 80 % transparency in the entire visible region. The cut-off wavelength of the grown crystal is 235 nm, and the optical band gap energy of IMGA was found to be 5.26 eV. The photocurrent study reveals that IMGA has a negative photoconductivity nature. Third-order nonlinear parameters were found by the Z-scan technique. IMGA has a self-defocusing nature, negative non-linearity, and saturated absorption properties. The calculated χ⁽³⁾ value is 2.045 x 10^-8 esu.