Evaluation of electronic and structural properties of scandium decorated graphenylene: A DFT-D3 study

Graphenylene (GPY) is a 2D sp2-carbon membrane with uniform pores. It has a unique structure which is composed ofperiodic pores with a diameter of 3.2 Å (A ring), cyclohexatriene-like units (B ring) and cyclobutadiene-like units (C ring). GPY is essentially a form of [N] phenylene [1].In this work, DFT-D3 calculations werecarried out using DMol3 module in Materials Studio software for condensed matter systems to model the surfaces of the electronic structures and the binding properties of the carbon allotropes [2].We used the generalized gradient approximation (GGA) method with the non-empirical local functional, and the Perdew-Burke-Ernzerhof correlation (PBE) and double numerical basis plus polarization (DNP) basis set. In all calculations, a 2×2 supercell of GPY was applied andafter optimization the lattice parameters of GPY obtained a = b = 6.764 Å. In GPY structure, there are single type of carbon atom, three types of C‒C bonds and three different polygons (A, B and C). We examined all of them to find desirable site for Sc adsorption. Results show that after optimization, Sc atom lies only in four sites contain center of ring A, B, C and top of the bond between A and B rings. Corresponding adsorption energies for these sites are ‒2.478, ‒3.949, ‒3.737 and ‒3.867 eV, respectively. Also, distances of Sc atom and GPY sheet in optimized structures are 0.0, 1.77, 1.97 and 2.0 Å, respectively. Therefore, B ring is the best position for Sc adsorption. Also, band structure diagrams show that pristineGPY is a semiconductor with a direct band gap of 0.862 eV. For Sc decorated GPY, we found that when Sc lies in rings A, B and C, obtained values for band gap are 0.0, 0.491and0.515 eV, respectively.It is seen that Sc decoration causes to decrease the band gap value. Also, PDOS diagrams show strong overlaps between carbon and metal atoms.