The electronic and optical absorption properties of pristine, homo and hetero Bi-nanoclusters

Abstract The TD-DFT and DFT calculations are applied to pristine, homo and hetero Bi nanoclusters based on additive acetylene; pyrrole and thiophene monomers. Results showed that linear optical properties are improved by additive thiophenes while nonlinear are enhanced by pyrroles. Hetero BiQD nanoclusters possesses a highly efficient linear and nonlinear optical responses than both pristine and homo nanoclusters. Particularly, hetero BiQD = C2N nanocluster are expected to be widely acknowledged in NLO devices. The optical absorption spectra also depend on the attached monomer, where the UV–Vis prominent absorption peak of pristine Bi flakes can be red shifted to higher wavelengths by attaching CHN and C2N while kept unchanged by attaching SN or NS. The red shift in the first case, the active electrons from monomer not only passivate the edged atoms but also decrease energy gap. Contradictory, in second case, the monomers acts as passivation element or group with unremarkable effect on energy gap.