Unidirectional growth of l-lysine l-lysinium dichloride nitrate (l-LLDN) single crystals by the SR method

Bulk semi-organic single crystals of l-lysine l-lysinium dichloride nitrate (l-LLDN) were grown by Sankaranarayanan–Ramasamy (SR) method. The experimental parameters involved in the present work are discussed in detail. The cut-off wavelength and the transmittance of the crystal were determined by UV–vis-NIR spectral analysis. Mechanical stability of the crystal was determined by Vickers microhardness tester. Refractive index of the crystal was measured using Brewster’s angle method. A simple interferometric technique was used for measuring birefringence of the crystal. The frequency dependent dielectric constant (εr) and dielectric loss (tan δ) were also measured. The results were analyzed for the l-LLDN crystals grown by both conventional and unidirectional methods.

Research highlights
► Growth of bulk l-LLDN single crystals by unidirectional solution growth method for the first time.
► Unidirectionally grown crystals have less defects.
► The double refraction was observed in unidirectionally grown l-LLDN single crystal.
► The unidirectionally grown l-LLDN crystal has better physical properties.