Non-linear optical response of meso substituted dipyrromethene boron difluoride dyes: Synthesis, photophysical, DFT and Z scan study

Abstract 2-(Naphthalen-2-yl)benzo[d]thiazole meso fused dipyrromethene boron difluoride dyes are synthesised and their linear and non-linear optical properties are studied. The third order nonlinear susceptibility (χ3) value obtained from the Z-scan experiment is 11.21 × 10−13 and 13.30 × 10−13 esu. The global hybrid (B3LYP and BHHLYP) and range-separated hybrid (CAM-B3LYP) functional with the basis set 6-311++G(d,p) performed better in computing the linear and non-linear optical properties. The computed β0 value (56.36 × 10−30 esu and 48.64 × 10−30 esu for Kr-OH-BDY and Kr-OMe-BDY respectively) of both the dyes are superior to that of urea (βo = 0.371 × 10−30 esu). Thermal and reorientational study display the dominating electronic contribution to the linear polarizability (α) whereas for first-order hyperpolarizability (β), pure vibrational contributions found to be more operative in both the dyes. The geometries of the dyes were optimized by using B3LYP/6-311++ G(d,p) level of theory.