First principles study of electronic and nonlinear optical properties of A-D-π-A and D-A-D-π-A configured compounds containing novel quinoline-carbazole derivatives

Materials with nonlinear optical (NLO) properties have significant applications in different fields, including nuclear science, biophysics, medicine, chemical dynamics, solid physics, materials science and surface interface applications. Quinoline and carbazole, owing to their electron-deficient and electron-rich character respectively, play a role in charge transfer applications in optoelectronics. Therefore, an attempt has been made herein to explore quinoline-carbazole based novel materials with highly nonlinear optical properties. Structural tailoring has been made at the donor and acceptor units of two recently synthesized quinoline-carbazole molecules (Q1,Q2) and acceptor-donor-pi-acceptor (A-D-pi-A) and donor-acceptor-donor-pi-acceptor (D-A-D-pi-A) type novel moleculesQ1D1-Q1D3andQ2D2-Q2D3have been quantum chemically designed, respectively. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) computations are performed to process the impact of acceptor and donor units on photophysical, electronic and NLO properties of selected molecules. The lambda(max)values (321 and 319 nm) forQ1andQ2in DSMO were in good agreement with the experimental values (326 and 323 nm). The largest shift in absorption maximum is displayed byQ1D2(436 nm). The designed compounds (Q1D3-Q2D3) express absorption spectra with an increased border and with a reduced band gap compared to the parent compounds (Q1andQ2). Natural bond orbital (NBO) investigations showed that the extended hyper conjugation and strong intramolecular interaction play significant roles in stabilising these systems. All molecules expressed significant NLO responses. A large value of beta(tot)was elevated inQ1D2(23 885.90 a.u.). This theoretical framework reveals the NLO response properties of novel quinoline-carbazole derivatives that can be significant for their use in advanced applications.