Nonlinear Optical (NLO) Response of Pristine and Functionalized Dodecadehydrotribenzo[18]annulene ([18]DBA): A Theoretical Study

The structural, electronic, and nonlinear optical (NLO) properties of pristine dodecadehydrotribenzo[18]annulene ([18]DBA) functionalizing with the alkali metal atom (Li and Na), NH2 and NO2 functional groups and its location are inspected through density functional theory (DFT) calculations. The NBO analysis indicates that functionalizing [18]DBA caused increasing charge transfer (CT) and introduced a new acceptor donor model for NLO materials due to the structure with of pi-electron of [18]DBA. The results demonstrate that the functional groups notably narrow the energy gap of [18]DBA, and the electronic character of [18]DBA is sensitive to the functional groups. Furthermore the considered functional groups enhance the static first and second hyperpolarizability of [18]DBA. Interestingly, replacement of H atom by Na and NO2 in [18]DBA leads to large static first hyperpolarizability (beta(0)) values of 3977.40 and 3722.56 au and very great static second hyperpolarizability (gamma(tot)) 980380.40 and 752886.20 au, respectively, which is the largest among the considered functionalizing structures. Also transition energies (Delta E) decrease due to functionalizing, and the best location for functionalizing is position 2.