http://197.159.135.214/jspui/handle/123456789/757 Thu, 23 Apr 2026 15:06:33 GMT 2026-04-23T15:06:33Z http://197.159.135.214/jspui/handle/123456789/805 Indoor LED Charging of Batteries with Organic Solar Modules Kone, Barry Energy harvesting inside buildings has received increasing attention as a way to improve the durability and battery life of electronic devices by harnessing ambient light sources. Organic solar modules offer unique advantages, such as flexibility, lightweight, and tunability, making them an attractive candidate for indoor energy harvesting applications. This thesis studies the feasibility of using organic solar modules for charging batteries by LED at 300-500 Lux under the condition of the different spectrum inside the house and in the office. Battery charging tests were performed to analyze the relationship between light intensity, efficiency of organic solar modules and battery charging capacity in indoor applications for charging electronic devices and miscellaneous under low light intensity. In this study, we demonstrated the possibility of charging a sodium anion battery coupled directly to an organic photovoltaic system under a 300-500 Lux LED corresponding to a light power density of 0.107-0.284 mW/cm2.The efficiency of the organic photovoltaic in this range was 4.98% and the efficiency of the PV-to battery was 3.25% and the overall efficiency was 3.07% under an LED light power density of 0.107-0.284 mW/cm2. With the different results we have obtained, and the success of the experiment, recharging electronic devices under indoor lighting with organic photovoltaic cells is feasible. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use, the Université Abdou Moumouni, Niger, and the Jülich Forschungszentrum in partial fulfillment of the requirements for the International Master Program in Renewable Energy and Green Hydrogen (Photovoltaics for Green Hydrogen Technologies) Thu, 28 Sep 2023 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/805 2023-09-28T00:00:00Z http://197.159.135.214/jspui/handle/123456789/804 Metallization of Silicon Heterojunction Solar Cells by Copper Paste Dispensing Mohamed, Issifi Yacouba In terms of global photovoltaic (PV) manufacturing capacity, crystalline silicon (c-Si)-based technologies account currently for 95% of the market, and one the most efficient technologies, among them, is the silicon heterojunction (SHJ) solar cell technology (efficiency above 26%). Nonetheless, this silicon-based photovoltaic is experiencing a threat due to the increasing price of silver, which is influenced by its shortage. For SHJ solar cells, silver usage for metallization accounts for approximately 25% of the total solar cell processing cost due to its large silver consumption. The findings emphasize that dispensed copper is a great alternative to silver for SHJ solar cell application, and it has a strong potential to reduce costs and improve cell efficiency. However, there are still obstacles to address for this technology. On one hand, dispenser printing technology needs to be improved in terms of printing quality, and on the other hand, copper reliability in terms of adhesion and electrical performance needs to be addressed. This research focuses on studying the characteristics of a single print dispensing, the process conditions of dispensed copper, the effect of those conditions applied to SHJ solar cells, and lastly the performance study of SHJ solar cells metalized with dispensed copper, then their comparison to other printing technology such as screen printing. It was found that dispensed Cu still has higher line resistance to screen-printed silver and that SHJ solar cells degrade above 280 ̊C and 5 s sintering conditions, though we could partly recover some loss with light soaking. SHJ solar cells metalized with dispensed Cu achieved an efficiency of>23% and a Voc of about 740 mV. This study advances SHJ solar cell technology by providing insights into the future potential of using dispensed copper metallization for improved and cost-effective solar cells. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use, the Université Abdou Moumouni, Niger, and the Jülich Forschungszentrum in partial fulfillment of the requirements for the International Master Program in Renewable Energy and Green Hydrogen (Photovoltaics for Green Hydrogen Technologies) Fri, 01 Sep 2023 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/804 2023-09-01T00:00:00Z http://197.159.135.214/jspui/handle/123456789/803 Characterization of Direct Light Soaking Effect on Transparent Passivating Contact Solar Cells Fall, Penda The optimization of a transparent, passivating, and conductive contact approach for the front side of silicon heterojunction solar cells has been widely studied due to the observed parasitic absorption losses in the amorphous silicon layers and the passivation losses during Indium Tin Oxide sputtering. To enable high efficiency crystalline silicon solar cells based on the combined front transparent passivating contact surface and rear silicon heterojunction structure, the present study focuses on curing the sputter damage by the application of light soa king without pre annealing treatment. The investigation of different light soaking conditions defines the heat assisted light soaking performed at 175 during 360s as a suitable operating condition to characterize the process on transparent passivating co ntact solar cells. The combination of heat and light during the curing process was found to be an inseparable effect in order to achieve better performance. A significant reduction in the open circuit voltage loss is observed after direct light soaking cur ing, resulting in a passivation recovery. The measurement of the photovoltaic parameters shows an interesting overall power conversion efficiency of 23.4% achieved for a n open circuit voltage of 736 mV, a fill factor of 80%, a short circuit current density of 39.75 mA/cm 2 and 1.146 Ω cm 2 as a contribution of series resistance. The study demonstrates the potential of direct light soaking to improve the transparent passivating and conductive contact solar c ells and contributes to a better understanding of the internal mechanisms involved. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use, the Université Abdou Moumouni, Niger, and the Jülich Forschungszentrum in partial fulfillment of the requirements for the International Master Program in Renewable Energy and Green Hydrogen (Photovoltaics for Green Hydrogen Technologies) Thu, 28 Sep 2023 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/803 2023-09-28T00:00:00Z http://197.159.135.214/jspui/handle/123456789/802 Simulations of Photoluminescence Transients in Perovskite Solar Cells Yoma, Kouroumlakiwe Perovskite solar cell technology has attracted enormous interest and attention from the research community in recent decades as one of the most promising photovoltaic technologies for future energy generation. This attention is partly due to the continuous increase in the power conversion efficiency of perovskite solar cells, which is approaching that of crystalline silicon technology, the ease of processing the materials, the availability of materials, and the low cost of manufacturing processes. However, the performance of perovskite solar cells is hampered by some charge carrier mechanisms and loss processes within the solar cell, thus hindering the large-scale development of perovskite solar cells. This work aims to simulate photoluminescence transients in complete perovskite solar cells to understand and gain insight into charge carrier dynamics in perovskite solar cells and different recombination mechanisms, as well as the effects of some material parameters on photoluminescence transients. Therefore, numerical simulations were carried out on a complete perovskite solar cell after excitation by a laser pulse by applying some key assumptions to the proposed model. The thesis explores the approach of a numerical model based on time-dependent derivative triple-coupled ordinary differential equations describing the kinetics of carriers within a complete perovskite solar cell using MATLAB software. To verify the reliability and accuracy of the numerical approach proposed in this work, experimental measurements of transient photoluminescence from a fabricated complete perovskite solar cell were performed. The results were compared with the SETFOS software to determine the correlation between experimental data and simulations. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use, the Université Abdou Moumouni, Niger, and the Jülich Forschungszentrum in partial fulfillment of the requirements for the International Master Program in Renewable Energy and Green Hydrogen (Photovoltaics for Green Hydrogen Technologies) Wed, 27 Sep 2023 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/802 2023-09-27T00:00:00Z