Design of a Novel Series of Donor–Acceptor Frameworks via Superalkali–Superhalogen Assemblage to Improve the Nonlinear Optical Responses

Abstract

Presently, many researches are directed toward the design of novel superatoms with high nonlinear optical responses. Inspired by a fascinating finding of superatoms which were designed by bonding superhalogen (Al nanocluster) with superalkalis (MO, M = Na and K), we suggest an effective strategy to form a series of typical donor-acceptor frameworks with high nonlinear optical responses via bonding the superalkalis MO (LiO, NaO, KO, LiNaO, LiKO, NaLiO, NaKO, KLiO, KNaO, and LiNaKO) with low ionization potential to the superhalogen Al with large electron affinity. The ionization potential, electronic spatial extent, electric field gradient tensors of O nuclei, and natural bond orbital charge values of the superalkalis MO were also calculated. We found that the M ligands have the remarkable effect on the ionization potential as well as O nuclear quadrupole resonance parameters of the superalkalis MO. Our results also represented that the bonding superalkalis can efficiently narrow wide HOMO-LUMO gap and considerably enhance first hyperpolarizability of the pristine Al, due to electron transfer in this type of superatom. Also, the effect of oriented external electric fields on the nonlinear optical responses of the superatoms MO-Al has been systematically explored. We found that the first hyperpolarizability of the superatom compounds can be gradually increased by increasing the imposed oriented external electric field from zero to the critical external electric field along the charge transfer direction (MO → Al). In this respect, this work reveals an effective approach to gradually enhance the nonlinear optical responses of the superatoms through applying oriented external electric fields.

Recent Progress on the Design, Characterization, and Application of Superalkalis

“…In addition, the potential application of using superalkalis as building blocks to design promising nonlinear optical (NLO) materials has been extensively explored in the past decade . First, a series of supersalts (BLi 6 ) + (X) − (X=F, LiF 2 , BeF 3 , BF 4 ), (M) + (BF 4 ) − (M=FLi 2 , OLi 3 , NLi 4 ), (M 3 O) + (Al 13 ) − (M=Na, K), (Na 2 X) + (Y) − (X=SCN, OCN, CN; Y=MgCl 3 , Cl, NO 2 ) were theoretically constructed and predicted to be new inorganic NLO molecules in view of their considerable NLO responses. Moreover, with their superior ability to offer valence electrons, superalkalis can serve as excellent sources of excess electrons to design unique compounds, such as electrides and alkalides, which exhibit extraordinarily large NLO responses.…”

Functionalized nona-silicide [Si9R3] Zintl clusters: a new class of superhalogens

“…, chlorine (Cl) atom with EA = 3.6 eV. The existence of superhalogens 28,29 was first predicted by Gutsev and Boldyrev in 1981 and later experimentally confirmed by Wang et al 30,31 Although several types of superhalogens are now available in the literature, 32–38 silicon-based Zintl superhalogens have not yet been reported. Here, we show that a functionalized nonasilicide Zintl cluster can be a potential superhalogen candidate, having oxidizing properties.…”

DFT study of superhalogen and superalkali doped graphitic carbon nitride and its non-linear optical properties

“…Four different complexes of superhalogen (BCl 4 ) and superalkali (NLi 4 ) doped GCN were investigated through density functional theory (DFT). [42][43][44] This study focused on the NLO response, electronic and molecular structure.…”