In this study, the optical refractive constants of the (5, 5) SWBNNT and (5, 5) SWCNT systems were calculated in both parallel and perpendicular directions of the tube axis by using Quantum ESPRESSO and YAMBO code. It also extended the optical behaviors of (5, 5) SWCNT and (5, 5) SWBNNT to both perpendicular and parallel directions instead of the parallel directions reported in the literature. It also looked at the effects of the diameter of the nanotube on the optical properties instead of chiral angles. From our results, the best optical reflection was found for (5, 5) SWBNNT, while the best optical refraction was found with (5, 5) SWCNT. It was observed that the SWCNT demonstrates refraction in both parallel and perpendicular directions, while (5, 5) SWBNNT shows perfect absorption in perpendicular direction. These new features that appeared for both nanotubes in perpendicular directions were due to new optical band gaps, which appear in the perpendicular directions to both nanotubes’ axis. The electron energy loss (EEL) spectrum of SWBNNT revealed the prominent π- and π + δ- Plasmon peaks, which demonstrates themselves in the reflectivity spectrum. Furthermore, little effect of diameter was observed for the perpendicular direction to both nanotubes’ axis; as such, the combined properties of (5, 5) SWBNNT and (5, 5) SWCNT materials/systems for transmitting light offer great potential for applications in mobile phone touch screens and mobile network antennas. In addition, the studies of optical properties in the perpendicular axis will help bring ultra-small nanotubes such as SWCNT and SWBNNT to the applications of next-generation nanotechnology.

This study investigates the effect of exchange-correlation on the electronic properties of hybridized hetero-structured nanomaterials, called single-walled carbon boron nitride nanotubes (SWCBNNT). A first principles (ab initio) method implemented in Quantum ESPRESSO codes, together with different parametrizations (local density approximation (LDA) formulated by Perdew Zunga (PZ) and the generalized gradient approximation (GGA) proposed by Perdew–Burke–Ernzerhof (PBE) and Perdew–Wang 91 (PW91)), were used in this study. It has been observed that the disappearance of interface states in the band gap was due to the discontinuity of the π–π bonds in some segments of SWCNT, which resulted in the asymmetric distribution in the two segments. This work has successfully created a band gap in SWCBNNT, where the PBE exchange-correlation functional provides a well-agreed band gap value of 1.8713 eV. Effects of orbitals on electronic properties have also been studied elaborately. It has been identified that the P^y orbital gives the largest contribution to the electrical properties of our new hybrid SWCBNNT nanostructures. This study may open a new avenue for tailoring bandgap in the hybrid heterostructured nanomaterials towards practical applications with next-generation optoelectronic devices, especially in LED nanoscience and nanotechnology.