Aneta Andruszkiewicz: Quantum Dots for Tandem Solar Cells Applications

Abstract

The recent acceleration of climate change has emphasized the urgent need for renewable energy solutions to mitigate the environmental impact of fossil fuel-based energy generation. Solar power stands out for this purpose because of its availability and capacity to meet global energy demands. Colloidal quantum dot (CQD) solar cells, have garnered attention for their unique optoelectronic properties, like tunable bandgaps, solution-processability and the ability to harvest infrared light. This PhD thesis presents a comprehensive investigation of CQD solar cells, and specifically the combination of CQD solar cells with other photovoltaic technologies. The research findings highlight both the potential of CQD-based tandem solar cells and the challenges for the CQD solar cells that must be addressed to enhance the solar to electricity conversion efficiency.

One focus of the research is the aspects of integrating CQD solar cells with other photovoltaic technologies, such as dye-sensitized and perovskite solar cells. These studies highlight the potential of CQDs to enhance infrared light absorption and energy conversion but reveal critical challenges related to charge recombination and interfacial losses in the CQD solar cell. To address these limitations, the CQD solar cell was investigated in more detail, especially with a focus on surface passivation and the investigation of charge carrier dynamics. Using advanced spectroscopic methods and photoelectrical methods, we could pin-point the most important limitations for the CQD solar cells. The findings demonstrated that effective surface passivation and the optimization of interfacial properties between the CQDs ant the charge extraction layers, are crucial for enhancing charge extraction and minimizing recombination losses in CQD-based solar cells. The results also highlighted the importance of further improve charge transport properties and reduce recombination rates, particularly for larger CQDs.

These insights show the need for continued research, combining advanced methods, surface ligand development and device engineering, to unlock the full potential of CQD solar cells in tandem applications.