Transition Metal Doped Boron Nitride Nanocages as High Performance Nonlinear Optical Materials: A DFT Study

In the current study, the exohedral doping of transition metals (TMs) in B12N12 nanocages is explored as a new approach to enhance the NLO response and electronic properties. In this regard, a thorough investigation of exohedrally doped B12N12 nanocages (M@x-Bl2N12; where M is for transition metals included Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and x = b(64), b(66), r(6) and r(4)) is performed. The TMs are doped over the bonds of BN (b(64)/b(66)), above four (r(4)) and six membered rings (r(6)). The spin polarized calculation data reveal that the most stable spin state increases from scandium (doublet) to manganese (sextet) and then decreases up to zinc (singlet). The binding energies of most of the complexes are in the range of - 12 kcal/mol to - 48 kcal/mol. NBO charges and bond order analysis are used to justify the nature and strength of interactions between TM and Bl2N12 nano-cage. TMs over B12N12 cause a significant reduction in the EH-L gap regardless of their doping position or atomic number. The highest decrease in EH-L gaps is observed in the case of Sc@b(66)-B12N12 (1.70 eV) compared to the bare B12N12 nano-cage (6.14 eV). This appreciable decrease in EH-L gap is observed due to generation of new energy level above the original HOMO of bare B12N12 nanocage. TMs doping causes a potential increase in the first hyperpolarizability (beta(0)) to 1.39 x 10(4) au for Sc@b(64)-B12N12 complex. TMs doped nanocages showed comparable NLO response to that of alkali metals doped analogues, which are considered best as best candidates for NLO response. These results will promote TMs doped B12N12 nanocage as a suitable candidate for designing potential NLO materials.