Abstract
To design suitable organic p-n junction diodes, modeling and simulation were performed for three donor-bridge-acceptor moieties using density functional theory. Three electron donor species namely TTF, DPh-BTBT and BEDT-TTF were connected to the electron acceptor TCNQ moiety through an insulating sigma bridge. The low HOMO-LUMO energy gap for these modeled species indicates that there is a good semiconducting route for electron transport between donor and acceptor moieties via an insulating bridge. The electric field was applied from donor to acceptor and from acceptor to donor moieties to further investigate the possible direction of charge transport. It has been observed that the HOMO-LUMO gap shrinks when the electric field direction is from donor to acceptor species and increases when the electric field direction is from acceptor to donor moieties.