The switchable chirality and optical properties of hexabenzo[a,c,k,m,u,w]trinaphthylene controlled by synergistic effect of static electric field and substituents: A DFT study

Abstract

This work selected the planar molecule hexabenzo [a,c,k,m,u,w]trinaphthylene (HBTN) with electron donor and acceptor, and introduced static electric field perpendicular to the conjugation plane for its control over molecular physical properties. With the guidance of electron donor and acceptor, controllable chirality, charge polarization, obvious charge transfer transition, Cotton effect and large NLO coefficients of molecule were obtained. The necessity of substituents to realize the control of static electric field to molecular chirality and optical properties was further confirmed by their locations and species. The direction of static electric field was also tested, and the importance of perpendicular field component was stressed. At last, the conclusion obtained via the discussion of monomer could also be applied to both homodimer and heterodimer, where same or different fragments were stacked via π-π interaction respectively. Especially for heterodimer, the completely different optical properties such as UV–Vis absorption spectra, ECD spectra and NLO coefficients between P- and M-type conformations were observed, and made it easier to recognize the chirality of heterodimer. All above results were meaningful to promote the application of molecules as chiral photovoltaic devices.