Structural, linear, nonlinear optical and thermal properties of 1,3-bis(4-methoxyphenyl)prop-2-en-1-one (BMP) single crystal grown by vertical Bridgman-Stockbarger technique

A nonlinear optical material of 1,3-bis(4-methoxyphenyl)prop-2-en-1-one (BMP), single crystal was grown using vertical Bridgman-Stockbarger technique under a vacuum atmosphere. The crystal structure and lattice parameters were determined using single-crystal X-ray diffraction (SXRD) analysis, which revealed that the BMP crystal belongs to orthorhombic system with a non-centrosymmetric space group. The lattice parameters were found to be a = 5.30 Å, b = 30.77 Å, c = 8.63 Å and bond angles α = 90 ̊, β = 90 ̊, ν = 90 ̊. Powder X-ray diffraction (PXRD) analysis confirmed the phase purity and crystalline nature of the BMP crystal with prominent (111) peak indicating high crystallinity. FTIR spectroscopy confirmed the presence of various organic functional groups, including aromatic rings, methoxy ethers, ethylenic groupsand 1,4- disubstituted benzene rings. UV- visible NIR spectroscopy revealed an optical transmittance of 56% in the visible to infrared region, with cut off wavelength of 425 nm. The optical band gap value is calculated at 2.91 eV. Thermogravimetric and differential thermal analysis (TG-DTA) showed the melting and freezing points of the BMP crystal to be 106 °C and 73 °C, respectively, with a supercooling temperature of 33 °C, an important parameter for melt growth technique. Second harmonic generation (SHG) efficiency was evaluated using the Kurtz–Perry powder technique, yielding an output signal voltage of 420 mV, which is 1.5 times higher than that of urea and 5 times higher than that of KDP. These results suggest that the BMP crystal is a promising candidate for linear and nonlinear optical applications.