Tunable optoelectronic properties of triply-bonded linear and graphynic carbon structures

In quest of novel materials for opto-electronic device applications, in this paper we present a computational study of electronic structure and optical properties of triply-bonded hydrocarbons with linear, and graphynic structures. Employ- ing a correlated electron methodology based upon the Pariser-Parr-Pople model Hamiltonian, and configuration interaction (CI) approach, structures containing up to 42 carbon atoms were studied. Our calculations, based upon large-scale CI expansions, reveal that the linear structures have intense optical absorption at the HOMO-LUMO gap, while the graphynic ones have those at higher energies. Thus, the opto-electronic properties depend on the topology of the graphynic structures, suggesting that they can be tuned by means of structural modifications. Our results are in very good agreement with the available experimental data.