Synthesis, optical, thermal and second harmonic generation studies of pure, urea and thiourea doped organic l-tartaric acid–nicotinamide (LTN) crystals

Nonlinear optical pure, urea and thiourea doped LTN crystals have been successfully grown from aqueous solution using slow evaporation technique. XRD analysis has been carried out to determine the lattice parameters of the pure and doped LTN crystals. The grown crystals were characterized by thermogravimetric analysis (TGA), differential thermal analysis (DTA), energy dispersive x-ray analysis (EDX) analysis and UV–vis–NIR spectroscopy. The fundamental modes of pure and doped crystals have been qualitatively assigned by FTIR analysis. The hardness of the grown crystals has been assessed and the results show the minor variation in the hardness value for the pure and doped LTN samples. Furthermore, second harmonic generation (SHG) measurements conducted indicate that the efficiency of thiourea doped LTN is 4.2 times greater than that of the KDP crystals and is suitable for frequency conversion applications.