Material synthesis, crystal growth, physico-chemical properties and second-order NLO activities of a novel L-histidinium phthalate potassium iodide (LHPPI) single crystal for NLO application

A novel nonlinear optical (NLO) single crystal of L-histidine phthalic potassium iodide (LHPPI) with dimensions of 8 × 8 × 3 mm3 was obtained from aqueous solution by slow solvent evaporation method. Single-crystal X-ray diffraction (SCXRD) results showed that the grown LHPPI crystal belongs to the orthorhombic crystal system with noncentrosymmetric space group P212121. Powder X-ray diffraction (PXRD) spectrum, the hkl plane orientations show the phase identity of the LHPPI crystal. The elemental composition of the grown LHPPI crystal was confirmed by EDS analysis. The functional groups were identified by fourier transform infrared (FTIR) study. The optical quality of the LHPPI crystal was studied using UV–Vis DRS spectrum analysis. The chemical etching studies were carried out to estimate the dislocation density. Vicker’s microhardness study revealed that the LHPPI crystal exhibits reverse indentation size effect (RISE) and belongs to soft category. The dielectric constant (εr) and dielectric loss (ε’) as a function of frequency were measured. The thermal properties of the LHPPI crystal were investigated by TG/DTA studies. The second harmonic generation (SHG) efficiency of the LHPPI crystal was measured by Kurtz–perry powder method. Thus, the results suggest that the LHPPI single crystal is of particular interest for NLO device application.