Tunable Optoelectronic Properties of Triply Bonded Carbon Molecules with Linear and Graphyne Substructures

Abstract

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

Systematic First-Principles Configuration-Interaction Calculations of Linear Optical Absorption Spectra in Silicon Hydrides: Si2H2n (n = 1–3)

“…For details of the MRSDCI approach adopted in this work, we refer the reader to our earlier works. [62][63][64][65][66][67][68][69][70][71][72][73] B. Computational parameters…”

“…Geometry optimization for all of the molecules considered was carried out by the coupled-cluster singles–doubles–triples (CCSD­(T)) level of theory, using large basis sets including polarization functions. The optical absorption spectra of various clusters were computed using the multireference singles–doubles configuration-interaction (MRSDCI) approach, which has been used by our group to study the optical properties of a variety of systems such as atomic clusters, − conjugated polymers, − and graphene quantum dots. , We would like to emphasize that the first-principles electronic structure studies of Si-based systems are more computationally expensive as compared to similar studies of clusters made up of smaller atoms, simply because Si has more electrons, thereby requiring larger basis sets and hence more computer memory and time. For Si 2 H 2 and Si 2 H 4 , the linear optical absorption spectra were computed for a number of isomers, with the aim of understanding the influence of geometry on the optical properties of these molecules.…”

Graphene quantum dots with Stone-Wales defect as a topologically tunable platform for visible-light harvesting

“…The one-electron hopping matrix elements t ij are restricted between nearest-neighbor carbon atoms i and j, with the value t 0 = -2.4 eV corresponding to uniform carbon-carbon bond-length r 0 = 1.4 Å, in accordance with our earlier calculations on conjugated polymers, polyaromatic hydrocarbons, and graphene quantum dots [18][19][20][21][22][23][24] . For the non-uniform bond-lengths, the values of corresponding t ij are determined from the exponential formula t ij = t 0 e (r 0 −r ij )/δ , extensively used by us earlier 25 , in which r ij is the distance between ith and jth carbon atoms (in Å), t 0 = -2.4 eV r 0 = 1.4 Å, and δ = 0.73 Å is a parameter depicting electron-phonon coupling.…”

Pariser–Parr–Pople Model Based Configuration-Interaction Study of Linear Optical Absorption in Lower-Symmetry Polycyclic Aromatic Hydrocarbon Molecules

“…t ij denotes the one-electron hopping matrix element, which in this work has been restricted to nearest neighbors only, with the value t 0 = 2.4 eV, in agreement with our previous works on πconjugated systems, such as conjugated polymers, 15,16 polycyclic aromatic hydrocarbons, 14,17−19 and graphene quantum dots. 20,21 To parametrize the Coulomb interactions, we used the Ohno relationship 28…”