Investigation on crystal growth and characterization of organic nonlinear optical triphenylmethane single crystal by vertical Bridgman technique

An organic triphenylmethane (TPM) single crystal of length 58 mm and diameter 12 mm was grown by vertical Bridgman technique. The cell parameters of the grown crystal were confirmed by single crystal X-ray diffraction studies. Powder X-ray diffraction analysis was used to determine the crystalline nature of the triphenylmethane crystal. The functional groups of the triphenylmethane crystal were identified by Fourier transform infrared analysis. The linear optical property of the grown triphenylmethane crystal was studied by UV-Vis-NIR spectroscopic analysis which shows that the crystal has low cutoff wavelength at 281 nm and exhibits optical band gap value at 4.15 eV. The fluorescence spectrum indicates that the grown crystal emits blue light. The second harmonic conversion efficiency of the crystal was determined using Kurtz and Perry powder technique. The thermal property of the grown crystal was analysed using thermo gravimetric analysis, differential thermal analysis and differential scanning calorimetry. The dielectric constant, dielectric loss and AC conductivity of the grown crystal was investigated for different frequency range upto 1 MHz at various temperatures. The strength of the crystal was estimated by Vicker's hardness test and laser damage studies.