Theoretical study of electronic and nonlinear optical properties of novel graphenylene-based materials with donor-acceptor frameworks.

A new functionalized graphenylene-based structure was designed by adsorbing of alkali metals M3 and superalkali M3O (M = Li, Na, K) on graphenylene (BPC) surface. The spectral data show that the spectral properties of the M3O@BPC system are very similar because the two-dimensional material plays a major role in the main transition. However, for M3@BPC system, the spectral shapes of the three systems show significant changes compared to each other because the different alkali metals play a major role in the main transition process. The calculation results show that the introduction of superalkali does not significantly increase the first polarizability; however, the introduction of alkali metals can obtain considerable nonlinear optical materials. For M3@BPC system, the first hyperpolarizability increases significantly when heavier alkali metal is introduced into the two-dimensional structure, which is found to be 866,290.9 au for K3@ BPC. A two-level model and first hyperpolarizability density can explain the large first polarizability of these systems.