Development and electronic performance of L-asparagine lithium nitrate crystals for nonlinear optical and photonic electronics

A novel semi-organic nonlinear optical crystal, L-asparagine lithium nitrate (LALN), has been synthesized by the slow solvent evaporation solution growth technique at room temperature. The crystalline nature of the grown crystal was characterized by the Powder X-ray diffraction (PXRD) method. The Fourier Transform Infrared Spectroscopy (FTIR) confirms the presence of the functional groups. UV–vis studies reveal a wide transparency window with an optical cutoff at 256 nm, corresponding to an estimated optical bandgap of 4.8 eV, signifying excellent optical quality with a low defect density. Thermo gravimetric analysis confirmed that the compound was stable up to 115 °C, whereas major decomposition occurred above 223 °C. The DTA curve depicts that the melting point of the LALN is around 271 °C. The elemental composition and presence were confirmed by EDAX analysis. Its relative SHG efficiency was found to be 0.65 times that of the standard potassium dihydrogen phosphate (KDP), confirming the non-centrosymmetric nature and significant nonlinear optical activity of the material. The dielectric studies showed frequency- and temperature-dependent polarization with low dielectric loss, hence confirming its suitability for optoelectronic devices.