| 초록 |
Molecular doping is a primary means to improve the electronic properties of organic semiconductor materials by increasing the concentration of charge carriers. Here, by using density functional theory, we have investigated the intermolecular charge transfer process between donor and acceptor molecules. We found that the full or near-zero amount of CT occurs in the weak electronic coupling regime depending on the sign of transfer level offset, that is, energy level difference between donor HOMO and acceptor LUMO. The partial CT occurs in the strong electronic coupling regime with linearity between the CT and the transfer level offset. We also showed that the normalized geometric changes during the CT process, λ, exponentially increases as the amount of CT increased. This exponential behavior is universal among the molecules we studied; that is, the amount of CT can be written only as a function of λ. Our findings are useful to find matching D-A pairs which have properties as desired. |
