Lanthanum (La) nanocomposites LaFeO3, LaNiO3, and LaCoO3 were synthesized using a sol-gel method, and different La to-metal (Fe, Ni, or Co) ratios were attained using various concentrations of salts. The resulting composites were calcined at 540 °C and characterized by XRD, SEM-EDX, FT-IR spectroscopy, XPS, thermogravimetric analysis (TGA), and PL spectroscopy. The activity of the lanthanum composites (LaFeO3, LaNiO3, and LaCoO3) was studied using the photocatalytic degradation of methylene blue (MB) and ortho-toluidine blue (o-TB) under visible light with a wavelength below 420 nm. The change in the concentration of dyes was monitored by using the UV-Vis spectroscopy technique. All composites appeared to have some degree of photocatalytic activity, with composites possessing an orthorhombic crystal structure having higher photocatalytic activity. The LaCoO3 composite is more efficient compared with LaFeO3 and LaNiO3 for both dyes. High degradation percentages were observed for the La composites with a 1:1 metal ratio.

Today, BHJ (bulk heterojunction) OSCs (organic solar cells) dominate modern age research in renewable solar energy. In recent developments, the ultimate goal is to improve the general performance of the BHJ-OSCs to enable them to compete on an equal footing basis with conventional silicon photovoltaic cells. In this presentation, we review the fundamental parameters that have been reported to improve the general performance of the BHJ-OSC devices. These parameters include, among other things, the use of ZnO nanoparticles ETL (electron transport layer) inserted between the top electrode and the photoactive layer, annealing procedure and device geometry. The BHJ-OSC devices constructed in this study comprised of successive (bottom up) layers of (3,4ethylenedioxythiophene):poly (styrenesulfonate) or PEDOT:PSS, a blend of poly (3-hexylthiophene) or P3HT and [6,6]-phenyl butyric acid methyl ester or PCBM, zinc oxide or ZnO nanoparticles and aluminum (Al) metal top electrode. These layers were deposited on ITO (indium tin oxide) coated glass substrates. The device construction was also inverted (top down) in order to evaluate the effect of inversion on the power conversion efficiency and the general performance of the devices. The devices were annealed at 155 o C either before (pre-annealed) or after (post-annealed) the deposition of the Al top electrode. Post-annealed devices showed improved PV (photovoltaic) characteristics when compared to pre-annealed devices. Furthermore, we discuss the performance of inverted geometry in comparison to ZnO nanoparticles and nanoflakes as buffer layers.