Biogenic Synthesis of Silver Nanoparticles with Antimicrobial Properties

The transmission of a wide range of diseases, related to the infection by pathogenic microorganisms is a major public health problem that daily endangers the safety of human population. Silver has been thoroughly studied and used against bacteria due to its antimicrobial properties. Nanostructured silver gathers all the advantages of the silver itself, as well as the advanced performance of the nanomaterials. Thus, currently, silver nanoparticles constitute the most widely used kind of nanoparticles in biomedicine, due to their attractive antimicrobial properties. A variety of physical and chemical methods are employed for the AgNPs synthesis. However, many of them include the use of toxic reagents or require large amounts of energy, during the synthesis process. For this reason, many eco-friendly methods are proposed in order to synthesize AgNPs. Hence, biogenic synthesis of AgNPs, utilizing biological resources opens a novel route for the development of alternative production processes.These methods seem to have significant advantages, as the extracts contribute positively to the formation and enhancement of the antimicrobial activity of AgNPs, also acting as protective agents of the produced particles. In this review an integrated approach of AgNPs bio-synthetic methods using microorganisms, such as bacteria and fungi, plants and plant extracts, as well as several templates, like DNA and viruses is discussed, shedding light on the comparative advantages of them.

Optical Properties of Carbon Doped by Nano Particle Titanium Dioxide to Enhance Solar Energy Absorption

The optical properties of carbon doped titanium oxide TiO2 were studied. The specimen prepared by utilizing spray pyrolysis method. The absorption coefficient, extinction coefficient, direct, indirect band gap, Urbach’s energy and high-frequency dielectric consistent with real and imaginary were investigated in the optical absorption spectral range of 200-1000 nm. The results showed the carbon is influenced TiO2 and has a semiconductor behavior; the energy gap was 3.15 eV of indirect transition and 3.2 eV for direct transition. The examination for the influence of TiO2 was an extension on the microstructure of carbon and it has an electrical behavior of the composite was distinguished. The modification of the substance structure of carbon by TiO2 doping permits photocatalytic movement of carbon towards the visible light and near infrared (NIR); this doped was gotten in a dry place at ambient temperature and its effect was expected from the physical properties of the energy gap, the advantages exhibited high absorption for spectral selective coating surfaces for operation by utilizing this coating on flat plate collector to give a high absorptivity from the solar energy respect to the incidence solar radiation.

High-Efficiency Solar Cells with a Planar Nanostructure Junction

Considering the current research interest in Organic / Inorganic (ZnO) hybrid solar cells structures in developing advanced photovoltaic devices, three different types of solar cell structures are proposed. In the proposed structures, hybrid solar cell composed of ZnO nanoparticles are used as an electron-acceptor material and PEDOT:PSS is intruded in between the nanoparticles, which reported to possesses power-conversion efficiency in excess of 8%. The use of p-ZnO layer results to improve the device performance on the rigid substrate. The power-conversion efficiency of the developed solar cell was found to be as high as 10% when measured under AM 1.5G illumination. Further, simulations have been carried out whose results are in line with experimental results.