4-Dimethylamino pyridinium p-chlorophenolate a novel third order nonlinear optical single crystal: growth and characterization

4-Dimethylaminopyridinium p-chlorophenolate (4DMAPCP) organic crystals were grown by slow evaporation solution growth technique using ethanol as solvent at room temperature. Single crystal X-ray diffraction studies shows that the material crystallizes in monoclinic system with centrosymmetric space group P 2₁/c and the cell parameters are observed to be a = 9.68 Å, b = 12.84 Å, c = 11.60 Å, Z = 4 and V = 1353 Å³. FT-IR and FT-Raman spectral studies were performed for analysing and assigning the vibrations and also to identify the functional groups. The optical transparency window in the visible and near IR (470–1100 nm) regions was found to be good, thus fulfilling the requirement for nonlinear optical applications. The optical band gap of the material was found to be 3.73 eV. Thermogravimetric analysis and differential thermal analysis showed that the compound decomposes beyond 250 °C. Dielectric loss and dielectric constant measurements as a function of frequency and temperature were measured for the grown crystal. Vicker’s hardness test reveals that 4DMAPCP belongs to the soft category. The laser induced surface damage threshold for the grown crystal is much greater than that of KDP. Third order nonlinear optical parameters like refractive index (n₂), absorption coefficient (β) and susceptibility (χ⁽³⁾) were assessed by Z-scan studies.