Today, most of the photovoltaic cells in the market are made of silicon. Great achievements are being attained every year in terms of reducing the price of this kind of cells and improving their efficiency, reliability and durability. However, further improving the cell performance is a challenging task because of the presence of optical, recombination and resistive loss mechanisms in the cell. This work is focused on the measurement and mitigation of these losses. Mitigation of the optical, recombination and resistive losses at first require quantifying those losses and their impacts on the cell performance metrics accurately. Traditionally, solar cells have been measured using characterization techniques like current-voltage, and Suns-Voc, which express the performance metrics in terms of the global cell parameters for the entire cell. However, solar cell is a large area device and different parts on a cell produce different amount of electricity because of the nonuniform distribution of the crystalline defects over the cell and the process variations. Spatial distributions of the cell parameters are valuable because they provide the in depth information about the root causes behind the performance drop of a cell, and points to its remedy. Camera based luminescence imaging and point by point measurement of quantum efficiency and reflectance on the cell are used in this work to find the spatial distribution of the parameters. A new method of parameter imaging is implemented by incorporating the quantum efficiency scanning with the luminescence measurement. A comprehensive methodology to evaluate losses and process variations in silicon solar cell manufacturing is also presented here. The nature of the distributions and correlations in this study provide important insights about loss mechanisms in industrial solar cells, helping to prioritize efforts for optimizing the performance of the production line. As an effort to mitigate the optical, recombination and resistive losses in the silicon solar cells, self-assembled multifunctional nanostructures are developed. These nanostructures can reduce the optical losses in the near band edge, thus contribute in increasing the photogenerated current density. They also contribute in reducing the surface recombination loss by passivating the silicon surface. Additionally, they shows promising results in reducing spreading resistance, which eventually helps the charge transport mechanism in the cell. An overview of the recent trends and endeavors in silicon photovoltaics is first given, followed by a chapter on the important concepts in silicon photovoltaics. The next chapter describes the solar cell manufacturing process and different performance issues related to it. Chapter 4 introduces different measurement techniques used for quantifying the optical, recombination and resistive losses. The following chapters present the crux of this work: method developed for measurement and mitigation of optical, recombination and resistive losses in silicon photovoltaics.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-2494 |
| Date | 01 January 2021 |
| Creators | Hossain, Mohammad Jobayer |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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