Effect of Graphene Oxide Nano-Sheets on Structural, Morphological and Photocatalytic Activity of BiFeO3-Based Nanostructures.

Photocatalysts are widely used for the elimination of organic contaminants from waste-water and H2 evaluation by water-splitting. Herein, the nanohybrids of lanthanum (La) and selenium (Se) co-doped bismuth ferrites with graphene oxide were synthesized. A structural analysis from X-ray diffraction confirmed the transition of phases from rhombohedral to the distorted orthorhombic. Scanning electron microscopy (SEM) revealed that the graphene nano-sheets homogenously covered La-Se co-doped bismuth ferrites nanoparticles, particularly the (Bi0.92La0.08Fe0.50Se0.50O3-graphene oxide) LBFSe50-G sample. Moreover, the band-gap nanohybrids of La-Se co-doped bismuth ferrites were estimated from diffuse reflectance spectra (DRS), which showed a variation from 1.84 to 2.09 eV, because the lowering of the band-gap can enhance photocatalytic degradation efficiency. Additionally, the photo-degradation efficiencies increased after the incorporation of graphene nano-sheets onto the La-Se co-doped bismuth ferrite. The maximum degradation efficiency of the LBFSe50-G sample was up to 80%, which may have been due to reduced band-gap and availability of enhanced surface area for incoming photons at the surface of the photocatalyst. Furthermore, photoluminescence spectra confirmed that the graphene oxide provided more electron-capturing sites, which decreased the recombination time of the photo-generated charge carriers. Thus, we can propose that the use of nanohybrids of La-Se co-doped bismuth ferrite with graphene oxide nano-sheets is a promising approach for both water-treatment and water-splitting, with better efficiencies of BiFeO3.

Influence of Refractive Index on Antireflectance Efficiency of Thin Films.

In today's world, scientific development is tremendously strengthened by imitating natural processes. This development remarkably validates progressive and efficient operation of multifunctional thin films in variable ecological circumstances. We use TFCalc thinfilm software, a reliable and trustworthy simulation tool, to design antireflective (AR) coatings for solar cells that can operate in varying environmental conditions and can be functional according to user-defined conditions. Silicon nearly reflects 36% light in the 550 nm wavelength region, causing a significant loss in solar cell efficiency. We used silicon as the substrate on which we designed and fabricated a trilayer inorganic oxide AR thin films, and this reduced it reflectance to <4% in the 300~800 nm wavelength range. Because of their distinguishing physical physiognomies, we used a combination of different inorganic oxides, comprising high-, low-, and medium-refractive indices, to model AR coatings in the desired wavelength range. Experimental implementation of the designed AR thin films in the present study unlocks new techniques for production of competent, wideband-tunable AR coatings that are applicable in high-performance photovoltaic applications.