Investigating the effect of adding silver nanoparticles to hybrid crystalline silicon solar cells

Hybrid silicon solar cells are an implementation of solar cells which have a simple fabrication process meanwhile absorbing a wider range of light spectrums compared to common silicon solar cells, although hybrid silicon solar cells have relatively low efficiencies. Metal nanoparticles have been known to enhance the performance of solar cells due to their localized surface plasmon resonance effect. The present study evaluates the addition of silver nanoparticles to enhance the properties and performance of hybrid silicon solar cells. In this regard silver nanoparticles are added to hybrid silicon solar cells producing different layer combinations in hybrid silicon solar cells. According to the results the addition of silver nanoparticles in specific combinations may enhance the performance whereas in other combinations may destroy the photovoltaic characteristics of the hybrid solar cell. A certain combination of the hybrid silicon solar cells including silver nanoparticles has been proposed wherein the properties of the cell are enhanced due to the plasmonic effect of silver nanoparticles. However, silver nanoparticles added on the surface of the photovoltaic cells cause shading, thus decreasing the active surface of the cell and thereby reducing the efficiency of the cells. Therefore, there is an optimum surface distribution for silver nanoparticles to benefit from the localized surface plasmon resonance effect meanwhile not shading a large amount of the cell and reducing the active surface area of the cell which is evaluated in the present research. Accordingly, by adding silver nanoparticles from a solution of 50% vl concentration the efficiency of the hybrid silicon cell reached 3.7% which is a significant increase compared to the efficiency of the ordinary hybrid silicon solar cells which was 1.8%

Gut microbiota and COVID‐19: A systematic review

Abstract Background and Aims Alteration in humans' gut microbiota was reported in patients infected with severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2). The gut and upper respiratory tract (URT) microbiota harbor a dynamic and complex population of microorganisms and have strong interaction with host immune system homeostasis. However, our knowledge about microbiota and its association with SARS‐CoV‐2 is still limited. We aimed to systematically review the effects of gut microbiota on the SARS‐CoV‐2 infection and its severity and the impact that SARS‐CoV‐2 could have on the gut microbiota. Methods We searched the keywords in the online databases of Web of Science, Scopus, PubMed, and Cochrane on December 31, 2021. After duplicate removal, we performed the screening process in two stages; title/abstract and then full‐text screening. The data of the eligible studies were extracted into a pre‐designed word table. This study adhered to the PRISMA checklist and Newcastle−Ottawa Scale Bias Assessment tool. Results Sixty‐three publications were included in this review. Our study shows that among COVID‐19 patients, particularly moderate to severe cases, the gut and lung microbiota was different compared to healthy individuals. In addition, the severity, and viral load of COVID‐19 disease would probably also be influenced by the gut, and lung microbiota's composition. Conclusion Our study concludes that there was a significant difference in the composition of the URT, and gut microbiota in COVID‐19 patients compared to the general healthy individuals, with an increase in opportunistic pathogens. Further, research is needed to investigate the probable bidirectional association of COVID‐19 and human microbiome