Investigations on the effect of transition metals on the growth and characterization of sodium acid phthalate single crystals

Sodium acid phthalate (SAP) C8H5NaO4 is one of the efficient semiorganic single crystals employed in second harmonic generation conversion applications. In the present work, optically transparent single crystals of SAP and 1 mol% of transition metals copper (Cu), nickel (Ni) and cadmium (Cd) doped SAP single crystals were grown by slow evaporation solution growth technique at ambient temperature. Powder XRD analysis revealed that all crystals exhibit orthorhombic crystal structure and the crystalline intensity was found to improve due to Cu dopant. The functional groups present in the grown crystal were identified by the FTIR analysis. The UV–vis–NIR study suggests that the crystals are highly transparent in the region 434–1200 nm and % of transmittance is increased by 20% in case of copper doped crystals. Concentration of the transition metals in the grown crystals were quantitatively confirmed from inductively coupled plasma optical emission spectroscopic (ICP–OES) studies. Improvement in second harmonic generation (SHG) efficiency due to transition metal dopants was observed and the thermal stability of pure and doped crystals were analyzed.