Investigation on growth, thermal, mechanical, dielectric, and NLO behaviour of 1-(4-methoxyphenyl)-3-(3,4,5-trimethoxyphenyl) single crystal grown by vertical Bridgman technique

The organic nonlinear optical material 1-(4-Methoxyphenyl)-3-(3,4,5-Trimethoxyphenyl) [MTP] was synthesised and grown as a bulk single crystal for the first time using the vertical Bridgman technique in a single-wall borosilicate glass ampoule. X-ray diffraction analysis confirmed that the grown MTP crystal belongs to the monoclinic system with centrosymmetric space group. FTIR spectroscopy identified the characteristic vibrational functional groups. UV-Vis-NIR spectroscopy revealed a lower cut-off wavelength of 439 nm, corresponding to 76% transmittance in the near-infrared region. Dielectric studies revealed a low dielectric constant and loss at higher frequencies, confirming favourable electrical properties. Chemical etching analysis was used to identify the surface defects and dislocations. Thermal stability was assessed through thermogravimetric and differential thermal analysis. Mechanical properties were evaluated using Vickers microhardness testing and laser damage threshold measurements. The nonlinear refractive index (n 2 ), absorption coefficient (β) and third order susceptibility (χ 3 ) have been calculated using Z-scan technique.