External electric field manipulating sequential and super-exchange charge transfer in donor-bridge-acceptor system in two-photon absorption

In this paper, we report external electric field manipulates sequential and super-exchange charge transfer in donor-bridge-acceptor (D-B-A) system in two-photon absorption (TPA). Our results reveal that the orientation and absorption strength of sequential and super-exchange charge transfer excitons can be well manipulated in DB-A system in TPA. The energy levels and absorption intensity of electronic transitions in one-photon absorption (OPA), as the intermediate state in TPA, are strongly influenced by external electric field, which provides a great opportunity for strong absorption with different charge transfer characteristics in TPA of D-B-A. Also, the optical properties of lowest charge transfer excited state under different external electric fields are also investigated in OPA. Our results can provide deeper understanding of external electric field in controlling sequential and superexchange charge transfer in D-B-A system in TPA.