Abstract
Molecular simulation based on Density Functional Theory was performed on the three donor-bridge-acceptor molecular systems. We choose Tetracyanoquinodimethane (TCNQ) molecule as an electron acceptor and three different molecules namely, Pentacene, Coronene and Diphenylpentacene as an electron donor. The donor and acceptor moieties were connected with a sigma bridge. After the modeling and optimization of these molecular systems, we performed electronic structure calculation. It has been observed that all these D-sigma-A molecular systems have low HOMO-LUMO gap which suggests that there is a good possibility of charge transport between donor and acceptor moieties via s bridge. To further explore the performance of these D-sigma-A molecular systems, the electric field was applied along the -X and+ X axis. It has been observed that HOMO-LUMO gap shrinks with the electric field along -X axis, however, with the electric field along+ X axis, HOMO-LUMO gap was initially augmented and later on shrinks with the high electric field.