Growth and characterization of pure and metals-doped organic nonlinear optical single crystal: L-alanine alaninium nitrate (LAAN)

摘要

The pure and metal ion (Cu~(2+), Zn~(2+) and Mg~(2+))-doped LAAN single crystal was developed by slow evaporation technique under ambient temperature. Cell parameters of the grown crystal were identified using single crystal X-ray diffraction analysis and found that the material crystallizes in orthorhombic crystal system with space group of P21.The presence of functional groups and the spectral properties were assessed by FTIR analysis. Transmittance spectrum reveals that the crystal has a low UV cut-off of 360 nm and has a good transmittance in the entire visible region. The band gap energy of LAAN and doped (Zn, Cu and Mg) LAAN crystals were estimated to be 3.38, 3.22, 2.75, and 3.13 eV by Tauc plot. Prevention of the recombination process of electron-hole pair was also confirmed by photoluminescence spectra analysis. The dielectric constant of pure crystal was found to be less than that of doped crystals. The AC conductivity was found to increase after doping and with the increase in temperature. Second harmonic generation efficiency of the grown crystal has been measured by Kurtz and Perry technique and it was found that Cu-doped LAAN is 3.2 times higher than that of KDP and 2.1, 1.5, and 1.8 times more prominent than pure, Zn, and Mg-doped LAAN crystals, respectively.