Giant first hyperpolarizabilities of donor-acceptor substituted graphyne: An ab initio study.

ABSTRACT

Graphyne (Gy), a theoretically proposed material, has been utilized, for the first time, in a phenomenal donor-Gy-acceptor (D-Gy-A) structure to plan a superior nonlinear optical material. Owing to the extraordinary character of graphyne, this conjugate framework shows strikingly extensive static first hyperpolarizability (ß(tot)) up to 128×10(-30) esu which is an enormous improvement than that of the bare graphyne. The donor-acceptor separation plays a key role in the change of ß(tot) value. The π-conjugation of graphyne backbone has spread throughout some of the D-A attached molecules and leads to a low band gap state. Finally, two level model clarifies that the molecule having low transition energy should have high first hyperpolarizability.