Theoretical study on design of novel superalkalis doped graphdiyne: A new donor–acceptor (D-π-A) strategy for enhancing NLO response

Abstract

Abstract Based on DFT calculations, we designed a new series of superalkali doped graphdiyne (GDY) complexes, M2X@GDY (M = Li, Na, K and X = F, Cl, Br) having electron donor and acceptor (D-π-A) framework. Our results of interaction energies reveal that these superalkalis are quite stable and chemisorbed over the 18 membered site of GDY. DFT results also reveal that the doping of superalkalis on GDY leads to narrowing of the HOMO-LUMO gaps, which enhance their conductance properties. Furthermore, the polarizability and first hyperpolarizability of GDY are enhanced dramatically up to 7.7 × 104 au. The enhanced first hyperpolarizabilities are further explained by two level model expression from TD-DFT calculations. The TD-DFT results show that all these designed superalkali doped graphdiyne complexes have ultraviolet light transparency. To rationalize the hyperpolarizability trend in superalkali doped GDY complexes, βvec calculations are also performed. This study may provide better understanding for the direct synthesis of new GDY based NLO materials in industries.