Enhanced NLO response in BODIPY-coumarin hybrids: density functional theory approach

Abstract

We have thoroughly investigated the first, second and third polarizability characteristics of four hybrid chromophores by spectroscopic and computational methods. B3LYP, CAMB3LYP and BHandHLYP functionals in combination with 6-311+G(d,p) basis set were used to evaluate the polarizability and hyperpolarizability characteristics of these chromophores. Generalized Mulliken Hush analysis and frontier molecular orbital electronic distribution images of chromophores obtained from Density functional theory computation has established the charge transfer characteristics of these hybrid chromophores. On the basis of charge transfer characteristic, these red absorbing and NIR emissive chromophores possess high nonlinear optical response. Comparison of isolated units with their analogous hybrid chromophores shows that fusion of coumarin with BODIPY enhances the nonlinear optical response. JCSC-D-17-00467 SYNOPSIS The NLO properties of coumarin-fused BODIPY hybrid chromophores were studied in details. Spectroscopic method gave rough estimation of polarizability and hyperpolarizability characteristics of four hybrid chromophores while computational approaches using three different hybrid functional, B3LYP, CAM-B3LYP and BHandHLYP in combination with 6-311+G(d,p) basis set, gave comparative estimation of these values. BLA/BOA calculations for ground and excited states suggested that the cyanine-type D- $$\pi $$ -A framework produces high NLO response. The hybrid molecules are proven to be the better performing NLOphores than the isolated coumarin or BODIPY units.