Through the first-principles calculations, a generalized theoretical framework is used to systematically investi-
gate the structural and electronic properties of the buckled SiC2 pentagon-based nanoribbons (p-SiC2 nano-
ribbons), including the formation energies, optimal structural parameters, phonon spectrum, electronic band
structures, orbital-projected density of states (DOSs) and partially charge density distributions. The dimensional
reduction of the pentagonal SiC2 nanosheet result in the four distinct edge structures of the p-SiC2 nanoribbons,
including ZZ-ribbon, ZA-ribbon, AA-ribbon and SS-ribbon, in which the p-SiC2 SS-ribbon achieves the greatest
thermal and dynamic stability among the other ones. Energy gaps of the p-SiC2 nanoribbons are created mainly
owing to the competition in the edge structures, finite-size confinements and asymmetry of chemical bonds in the
tetrahedral lattice. The critical width is found at W = 14, where the band gaps are dramatically reduced as the
widths increase below the critical one, while the band gaps are hardly sensitive with the enlarged widths beyond
the critical one. The unusual properties of the p-SiC2 nanoribbons is very potential for applications in opto-
electronic devices, especially in photovoltaics.