Investigation on new NLO material L-histidine potassium pentaborate (LHKB5)

Abstract

A new nonlinear optical crystal L-histidine potassium pentaborate single crystal was grown from aqueous solution by the slow evaporation solution growth technique to analyse its suitability for NLO device applications. It belongs to the orthorhombic crystal system which is confirmed by single crystal X-ray diffraction analysis. The UV-visible analysis was carried out on LHKB 5 crystal to find out cut-off wavelength and the energy gap of the material was found to be 245 nm and 5.05 eV. The presence of L-histidine potassium pentaborate on grown material was confirmed by FTIR analysis. TG-DSC analysis determines that the material has two stages of decomposition and it has three stages of weight loss. From DTA curve a sharp endothermic peak at 192.45°C shows good crystallinity and corresponds to the melting of the grown crystal. The mechanical strength of the material is calculated using Vicker's microhardness. Grown crystal shows that the material is very much suitable for a second harmonic generation and frequency conversion applications.