Theoretical Study On The Electronic And Nonlinear Optical Properties Of Superalkali-doped Inorganic Boron Nanocages

With the extensive application of nonlinear optical(NLO)materials in the fields of optical communication,optical computer and optical information processing etc.,it has become a hot topic to design the high-performance NLO materials.Many studies revealed that the materials with the typical Donor-Acceptor framework can usually produce the outstanding NLO responses due to the occurrence of evident charge transfer process in systems.Currently,constructing the typical charge-transfer framework by choosing the appropriate donor and acceptor groups has been becoming an effective strategy to achieve the considerable NLO response.Recently,B40 nanocage has been successfully fabricated in experiment(Nat Chem,2014,6,727),and it can possess the considerably large electron affinity(EA),indicating the strong electron-withdrawing ability.Inspired by this fascinating finding,we propose a new and effective strategy to construct a series of typical Donor-Acceptor(D-A)frameworks via linking the superalkali M3O(M = Li and K)unit with the low ionization potential to the B40 nanocage with large electron affinity.By means of the density functional theory computations,we have systematically investigated the structures,electronic properties,the first and second hyper-polarizabilities of these modified B40 nanocage systems.Owing to the formation of a B-O chemical bond,these composite systems(M3O)n-B40(M = Li and K,n = 1 and 2)can possess the considerably large binding energy ranging from 57.0 to 99.8 kcal/mol,indicating their high structure stabilities.Compared with the pristine B40 nanocage,linking the superalkali M3 O can effectively narrow the wide energy gap from the original 2.86 e V to 0.61~1.11 e V,and significantly increase the first and second hyperpolarizabilities to as large as 5.00�104~2.46�105 au and 1.48�107~ 4.85�108 au,respectively,owing to the occurrence of evident electron transfer process in this kind of typical D-A framework.These fascinating findings will be advantageous for promoting the potential applications of the inorganic boron-based nanosystems in the new type of electronic nanodevices and high-performance nonlinear optical materials.