Growth and characterizations of pure and Cu-doped imidazolium L-tartrate (IMLT) single crystals: optical and NLO properties

Good-quality single crystals of pure and copper (Cu)-doped imidazolium L-Tartrate (IMLT) are grown up from aqueous solution by slow solvent evaporation technique. Monoclinic crystal system with P21 space group was identified for both pure and Cu-doped IMLT crystals. The UV-Vis transmittance spectrum shows that the crystal has a good optical transmittance in the entire visible region with lower cut-off wavelength 314 nm. The vibrational frequencies of various functional groups in the crystals have been derived from FTIR analysis. The grown crystal shows good crystalline quality and optical transparency, according to structural and optical data. The mechanical study on the (010) plane of the IMLT single crystal analyzed by Vickers microhardness tester reveals the moderate hardness of the material. We measured the wavelength-dependent refractive index and the piezoelectric d33 coefficient. Cu doping in the IMLT crystal also boosted the dielectric properties, durability, and SHG conversion efficiency. Pure and Cu-doped IMLT crystals have second harmonic efficiency of 1.76 and 2.45 times that of ordinary KDP, respectively. As a result, the SHG efficiency of the Cu-doped IMLT crystal is higher. All the findings in the present work indicate that Cu-doped IMLT has a potential application as a useful NLO candidate.