Optical investigations on Tb3+ doped l-Histidine hydrochloride mono hydrate single crystals grown by low temperature solution techniques

Abstract

The potential nonlinear optical material of Terbium (Tb3+) ion doped l-Histidine hydrochloride monohydrate (LHHC) single crystals were successfully grown. Tb3+:LHHC crystals of 7mm×5mm×3mm and 59mm length and 15mm diameter have been grown by the slow solvent evaporation and Sankaranarayanan-Ramasamy (SR) techniques respectively. The grown crystals were characterized by single crystal X-ray diffraction analysis to confirm the crystalline structure and morphology. High resolution X-ray diffraction (HRXRD) studies revealed that the SR grown sample shows relatively good crystalline nature with 9″ full-width at half-maximum (FWHM) for the diffraction curve. Functional groups were identified by Fourier transform infra-red spectroscopy (FTIR). The optical transparency and band gaps of grown crystals were measured by UV–Vis spectroscopy. Thermogravimetric and differential thermal analysis (TG/DTA) studies reveal that the crystal was thermally stable up to 155°C in SR grown crystal. Surface morphology of the growth plane was observed using scanning electron microscopy (SEM). The incorporation of Tb ion was estimated by EDAX. The frequency-dependent dielectric properties of the crystals were carried out for different temperatures. Vickers hardness study carried out on (100) face at room temperature shows increased hardness of the SR method grown crystal. Second harmonic generation efficiency of SEST and SR grown crystals are 3.2 and 3.5 times greater than that of pure KDP. The Photoluminescence (PL) studies of Tb3+ ions result from the radiative intra-configurational f-f transitions that occur from the 5D4 excited state to the 7Fj (j=6, 5, 4, 3) ground states. The decay curve of the 5D4 level of emission was observed with a long life time of 319.2041μs for the SR grown Tb3+:LHHC crystal.