Here we proposed a novel two-dimensional (2D) carbon allotrope namely pentagraphyne (PG-yne) which is energetically favourable than other graphyne members, including experimentally synthesized graphyne and graphdiyne monolayer. State-of-the-art theoretical calculations...

Using density functional theory calculations, we have analyzed nonlinear optical properties of a series of T-graphene quantum dots differing in their shape and size. Electronic polarizability and first-order and second-order hyperpolarizability of these systems are investigated and shed light on their stability and electronic properties. Negative cohesive energy shows that they are energetically stable. The effect of size and incident frequency on their nonlinear responses are comprehensively discussed. Most of the systems exhibit a strong NLO response, and it is enhanced in the presence of an external field. All these systems show absorption maximum ranging from UV to visible window. Overall, this theoretical framework highlighted the nonlinear optical properties of T-graphene quantum dots that may provide valuable information in designing potential NLO materials.

We present a systematic study on structural, electronic, optical properties of C30 fullerene and its six doped counterparts, C10X10Y10 (where, X=B, Al and Y=N, P, As) based on density functional theory calculation. All the fullerenes are energetically stable with cohesive energy per atom ranging from −5 to −8 eV. Chemical reactivity parameters are significantly enhanced due to doping. Further, nonlinear optics reveal that dopants bring remarkable change in polarizability and first hyperpolarizability of C30 derivatives. This work ensures the important implementations of these systems in nonlinear optics as well as for designing optical protective materials. Finally, the electronic absorption spectra predict the possibility of using C30 and heterofullerenes as photocatalyst in the visible region and UV light protection material in the UV region.

Utilizing first-principles calculations, we studied the electronic and optical properties of C, CXY, and XY fullerenes (X = B, Al; Y = N, P). These fullerenes are energetically stable, as demonstrated by their negative cohesive energies. The energy gap of C may be tuned by doping, and the BN fullerene was found to have the largest energy gap. All of the fullerenes had finite optical gaps, suggesting that they are optical semiconductors, and they strongly absorb UV radiation, so they could be used in UV light protection devices. They could also be used in solar cells and LEDs due to their low reflectivities. Graphical abstract Possible applications of doped C fullerene.