Structure, optical, thermal, dielectric, hardness behaviors of l-histidine barium nitrate (LHBN): a metal-organic crystal for optoelectronic applications

Abstract In the search for advanced materials for photonics and optoelectronic device fabrications, l -histidine – based metal – organic crystals have shown a remarkable contribution due to their nonlinear optical properties. However, the comprehensive investigations incorporating structural, thermal, mechanical and dielectric properties into a single framework remain scarce. In the current work, we report the growth of a novel semi-organic nonlinear optical crystal, l -histidine barium nitrate (LHBN), using the slow cooling technique. The synthesis involves mixing histidine and barium nitrate in a 1:1 M ratio. Single crystals of approximately 10 mm in size were obtained within 45 days. The crystallization process of LHBN was confirmed through single crystal X-ray diffraction analysis, revealing a monoclinic system with non-centrosymmetric space group C2. FTIR spectroscopy was used to find functional group vibrations and the transmission spectrum was recorded in the solution state to show the lower cut-off frequency. The materials exhibited excellent optical transparency with a lower cut-off wavelength at 226 nm. Thermal stability of the grown crystal up to 240 °C was observed using TGA/DTA analysis. The mechanical and dielectric properties of the grown LHBN crystals were evaluated along the (0 1 0) crystallographic plane. Dielectric analysis proved the frequency dependent permittivity with low dielectric loss at high frequencies, which makes the materials for NLO applications. Additionally, the optical nonlinearity of the crystal was confirmed using the Kurtz powder technique, which demonstrated its high second harmonic generation efficiency with 2.2 times that of KDP.