Abdelghani Lakhdari

Amorphous silicon (a-Si) is rarely used for large scale photovoltaic energy production, it remains relevant in flexible electronic applications, where mechanical flexibility and lightweight design are prioritized, where exposure to sunlight is typically limited or irregular. This study conducts an experimental analysis of the long-term aging effects on the proprieties of an amorphous solar cells, under five years of intermittent outdoor climate conditions. Unlike conventional aging studies that focus on degradation over time, this research highlights the cumulative effects of environmental exposure, considering the discontinuous nature of exposure cycles and the non-linearity of degradation phenomena because of the abrupt transitions between outdoor exposure phases and indoor laboratory rest periods. The results show that nearly 50% of the panel’s performances is reduced, with the losses observed as follows: a substantial decline in the fill factor from 55.3% to 30%, a decrease in energy conversion efficiency from 11.36% to 5.5%. This accelerated deterioration mainly attributed to harsh environmental transitions caused by intermittent exposure, which amplify aging mechanism compared to continuous exposure. Beyond the experimental findings, the approach presented here, constitutes a meaningful scientific contribution. By introducing a realistic and underexplored aging scenario, it lays the groundwork for a new line of research.

Due to the development of microfluidic systems biomedical microelectromechanical systems (BioMEMS) for magnetic labelling detection by magnetic microbeads circling in microfluidic channels, we used the magnetic field created by microcoils. The magnetic field associated with the electric current, but with negatively affects if its value increases too much. Handling bio-species in the microfluidic chip requires that the temperature maintained to keep the cells to prevent their destruction. In this paper we have described the spiral square coil design of different structures to produce an effective magnetic flux density. The simulation of the magnetic flux density is carried out with the help of the COMSOL software. We have presented an optimization of the geometric parameters of the microcoil for a better performance and a miniaturization of the structure with copper wire section S=25 µm2 and inter-wire space a=5 µm. We have also developed this microcoil by adding a ferromagnetic core to the inner center, the results obtained in this work shown that the magnetic flux density increases around 1.07 times in Bx and 1.45 times in Bz. This new approach in designing a microcoil allows to obtaining a fast trapping of the microbeads and a highly sensitive biological element detection and avoiding increase heat ratio in microfluidic systems.