Developed performance of rGO/p-Si Schottky junction solar cells

Graphene in combination with Si has been extensively used to prepare efficient and stable p-graphene/n-Si Schottky junction solar cells. In contrast, there is a difficulty in including graphene within the fabrication process of efficient and stable n-graphene/p-Si Schottky junction solar cells. The reason for this is that there is a challenge in achieving an effective and stable n-doping process for graphene or rGO due to the ambient environment. In this work, a novel approach is introduced for preparing more efficient, stable, larger and simpler n-rGO/p-Si Schottky junction solar cells. The n-rGO rather than graphene, which has been successfully developed using NH3 molecules, is included in the fabrication process of n-rGO/p-Si Schottky junction solar cells. Accordingly, the power conversion efficiency of 9.7 was obtained for prepared devices after applying ammonia treatment for 3 h. For the first time, the developed n-rGO layers are also excellently employed to prepare large n-rGO/p-Si Schottky junction solar cells with ideal J-V curves. The improved efficiency of 12.6 % is reached for n-rGO/p-Si Schottky junction solar cells prepared with an active area of 0.6 cm2. To improve the stability, devices are coated with PMMA as an encapsulated layer, leading to an improvement in the stability for 2 months in the ambient air. Additionally, a recorded efficiency of 13.8 % is achieved. We attribute this development to the chemisorption of ammonia molecules on rGO, which effectively develops the performance of devices

Anti-capsular activity of CuO nanoparticles against Acinetobacter baumannii produce efflux pump

Copper oxide nanoparticles are modern kinds of antimicrobials, which may get a lot of interest in the clinical application. This study aimed to detect the anti-capsular activity of CuO nanoparticles against Acinetobacter baumannii produce efflux pump. Thirty-four different clinical A. baumannii isolates were collected and identified by the phenotypic and genetic methods by the recA gene as housekeeping. Antibiotic sensitivity and biofilm-forming ability, capsular formation were carried out. The effect of CuO nanoparticles on capsular isolates was detected, the synergistic effects of a combination CuO nanoparticles and gentamicin against A. baumannii were determined by micro broth checkerboard method, and the effect of CuO nanoparticles on the expression of ptk, espA and mexX genes was analyzed. Results demonstrated that CuO nanoparticles with gentamicin revealed a synergistic effect. Gene expression results show reducing the expression of these capsular genes by CuO nanoparticles is major conduct over reducing A. baumannii capsular action. Furthermore, results proved that there was a relationship between the capsule-forming ability and the absence of biofilm-forming ability. As bacterial isolates which were negative biofilm formation were positive in capsule formation and vice versa. In conclusion, CuO nanoparticles have the potential to be used as an anti-capsular agent against A. baumannii, and their combination with gentamicin can enhance their antimicrobial effect. The study also suggests that the absence of biofilm formation may be associated with the presence of capsule formation in A. baumannii. These findings provide a basis for further research on the use of CuO nanoparticles as a novel antimicrobial agent against A. baumannii and other bacterial pathogens, also to investigate the potential of CuO nanoparticles to inhibit the production of efflux pumps in A. baumannii, which are a major mechanism of antibiotic resistance