Theoretical study on the structural, electronic, and optical properties of B_nC_n (n = 1–13) clusters

Abstract

We applied density functional theory (DFT) calculations to investigate the low-energy geometries and electronic characteristics of stoichiometric B n C n (n=1-13) clusters. We performed harmonic vibration frequency analysis to ensure that the ground-state isomers are the real local minima. B n C n clusters tend to evolve from planar and annular structures to quasiplanar bowl structures to maintain the lowest structural energy as cluster size n increases. The clusters with even n have large HOMO-LUMO gaps and high stability. We used the time-dependent DFT (TDDFT) calculations to acquire the optical absorption spectra for the lowest-energy B n C n (n=4, 6, 8, 10, 12) clusters. The clusters exhibit strong absorption in the ultraviolet region. With the increasement of n, the absorption of clusters, particularly that of the B 8 C 8 cluster, intensifies in the visible region. Therefore, the clusters investigated in this work can be used to fabricate novel two-dimensional materials for visible-light absorption and have potential applications in various fields, such as catalysis.