Growth, XRD, optical, thermal, mechanical, electrical and NLO studies on mixture of potassium hydrogen phthalate and L-tartaric acid crystal for NLO applications

The mixture of potassium hydrogen phthalate and L-Tartaric acid crystal was synthesized by slow evaporation method. The synthesized crystals were analyzed for their structural, optical, mechanical and electrical properties. The single crystal X-ray diffraction study gives the unit cell parameters and confirms its triclinic system. The powder X-ray diffraction analysis shows that the sample is in pure crystalline form. Synthesized crystal optical absorption was investigated by UV–Vis analysis. The functional groups, that were present in the sample, were identified by the FTIR spectrum. A strong emission due to f-d transition at 356 nm was observed in the photoluminescence spectrum. The positive photoconductivity behavior of the crystal was observed in photoconductivity study. The good NLO second harmonic efficiency (1.1 times that of KDP) shows its suitability for device applications. It is observed from the TG–DTA studies that the crystal is stable up to 224 °C. The mechanical behavior and the associated parameters were estimated. To ensure its electrical property, dielectric and ac conductivity studies were made.