Perovskite solar cells (PSCs) have drawn significant consideration as a competing solar cell technology because of the drastic advance in their power conversion efficiency (PCE) over the last two decades. The interfaces between the electron transport layer (ETL) and the absorber layer and between the absorber layer and the hole transport layer (HTL) have a major impact on the performance of the PSCs. In this paper, we have investigated the defect interfaces between ETL/absorber layer and absorber layer/HTL of calibrated experimental lead-based and lead-free PSCs. The influence of the defect interfaces is studied in order to find the optimum value for the maximum possible PCE. While the PCE has not been enhanced considerably for the lead-based, it is boosted from 1.76% to 5.35% for lead-free PSCs. Also, bulk traps were found to have minor role in comparison with interface traps for the lead-free cell while they have a significant impact for the lead-based cell. The results presented in this work would shed some light on designing interface defects of various types of practical PSC structures and demonstrates the crucial impact of the interface defects on lead-free vs lead-based PSCs. All simulation studies are performed by using SCAPS-1D simulator.

Recently, there is a rapid trend to incorporate low cost solar cells in photovoltaic technology. In this regard, low-cost high-doped Silicon wafers are beneficial; however, the high doping effects encountered in these wafers render their practical use in fabrication. The npn solar cell microstructure has been found to avoid this issue by the proper design of vertical generation and lateral collection of the light generated carriers. We report on the impact of the p + base doping concentration, up to 2×10 19 cm-3 , on the npn microstructure performance to find the most appropriate way for high efficiency. To optimize the structure, a series of design steps has been applied using our previously published analytical model. Before inspecting the high doped base effect, firstly, the n + emitter is optimized. Secondly, the impact of bulk recombination inside the p + base is introduced showing the range of optimum base width (Wp). Then, we investigate thoroughly the impact of base doping levels for different base widths to get the optimum Wp that satisfies maximum efficiency. The results show that for p + base doping concentration ranging from 5×10 17 cm-3 to 2×10 19 cm-3 , the npn microstructure efficiency decreases from 15.9% to 9%, respectively. Although the efficiency is degraded considerably for higher doping levels, the structure still achieves a competitive efficiency at higher doping levels, for which its cost is greatly reduced, in comparison with thin film solar cells. Moreover, using higher doping permits lesser wafer area which could be beneficial for large area solar cells design.

Abstract-This paper aims to design size and implement a Photo Voltaic system (PV system) for powering a living room.The required load to be powered by the PV system is completely determined. A comparison between using normal and power saving loads is carried out. The power saving loads is chosen to reduce the overall cost of the required system. The proposed PV system for powering the predetermined load is introduced. Each part of the system is designed and sized based on the load requirement. Finally, the practical implementation for the overall PV system for powering the required load is done. The implemented system works in an efficient way.