Influence of push-pull configuration on the electro-optical and charge transport properties of novel naphtho-difuran derivatives: a DFT study

Abstract

We present a density functional theory (DFT) study pertaining to electro-optical and charge transport properties of two novel derivatives of diphenyl-naphtho[2,1-b:6,5-b′]difuran (DPNDF) as investigated based on push-pull configuration. Both molecular structures of the designed derivatives were optimized, in ground state (S0) as well as excited state (S1), using DFT and time-dependent DFT (TD-DFT) respectively. The push-pull configuration effect was studied meticulously for different electro-optical properties including adiabatic/vertical electron affinity (EAa/EAv), adiabatic/vertical ionization potential (IPa/IPv) and hole/electron reorganization energies (λh/λe), hole/electron transfer integrals (Vh/Ve), hole/electron mobility and photostability. We observed smaller λe, improved Ve and higher electron mobility for compound 1 compared with the parent molecule. Our calculated value of the electron mobility for compound 1 (2.43 cm2 V-1 s-1) revealed it to be an efficient electron transport material. Moreover, the influence of the push-pull on the electronic structure was also investigated by calculating the total and partial density of states (DOS). Taking advantage of the strong push-pull configurations effect on other properties, the study of the designed chemical systems was extended to their nonlinear optical (NLO) properties. Our designed novel derivatives (1 & 2) exhibited significantly larger amplitude values for first hyperpolarizability with βtot equal to 209.420 × 10-30 esu for compound 1 and 333.830 × 10-30 esu for compound 2. It was found that the first hyperpolarizability and HOMO-LUMO energy gap are in an inverse relationship for compounds 1 and 2.