A theoretical approach towards designing of banana shaped non-fullerene chromophores using efficient acceptors moieties: exploration of their NLO response properties.

Current research has focused on utilization of non-fullerene based organic materials for the advancement of nonlinear optical (NLO) based technology. The reference compound (DTPSR1) was used in tailoring process to design seven new derivatives (DTPSD2-DTPSD8) via various acceptor moieties. The M06-2X level with 6-311G(d,p) basis set was used for assessing frontier molecular orbitals (FMOs), natural bonding orbital (NBO), nonlinear optical properties [average polarizability < α > , first hyperpolarizability (βtotal), second hyperpolarizability (γtotal)], transition density matrix (TDM) and UV–Vis analyses of DTPSR1 and DTPSD2-DTPSD8. The UV–Vis analysis indicated that the designed derivatives show comparable results (515.462–586.269 nm) with reference molecule (583.592 nm), except DTPSD7, that exhibited slight red shift (586.269 nm). Smaller LUMO–HOMO energy gaps were reported as in DTPSD3 (3.53 eV), DTPSD7 (3.53 eV) and DTPSD8 (3.55 eV) as compared to DTPSR1 (3.60 eV) which was further supported by TDM analysis. The global reactivity descriptors have also shown close correlation with LUMO–HOMO energy gaps; smaller value of energy gap showed lower hardness value 1.77 eV for DTPSD3, DTPSD7 and DTPSD8 and greater softness values 0.283 eV for DTPSD3, DTPSD7 and 0.281 eV for DTPSD8, respectively. The hyper conjugative interactions, stability, and electron-transfer mechanism were elucidated by using NBO analysis. DTPSD2-DTPSD8 also exhibited comparatively closer NLO results with DTPSR1. Among DTPSD2–DTPSD8, the highest ⟨α⟩1439.16 a.u, βtotal 189,720.546 a.u and γtotal 1.980890 × 107 a.u were observed for DTPSD7. It is anticipated that our study would provide a springboard to attain the NLO materials exhibiting significant future applications such as in telecommunication, data storage and optical poling. [ABSTRACT FROM AUTHOR]