Developing new indicators for identifying degradation mechanisms of solar cells

Alghlaigah, Abdulaziz 2026. Developing new indicators for identifying degradation mechanisms of solar cells. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Solar cells convert light into electric energy based on the photovoltaic effect. They are one of the most important renewable energy technologies of the future. A crucial factor that determines the economic viability of this technology is its long-term stability. The research effort in this aspect requires the ability to identify the exact degradation mechanisms. The aim of this project is to explore the potential correlation between the degradation mechanisms and the photovoltaic parameters and, consequently, demonstrate the feasibility of identifying degradation mechanisms using the current–voltage (I-V) and impedance spectroscopy (I-S) measurements. Systematic experiments were performed using monocrystalline silicon solar cells to investigate the effects of degradation mechanisms on the photovoltaic parameters. The experimental work carried out in this thesis produced a wealth of original data on the response of the photovoltaic parameters to a series of controlled treatments of different degradation mechanisms, including broken contact fingers, surface scratching, heat treatment, and partial shading. The analysis of the results shows clearly the correlation between specific treatments and the patterns of the changes in the photovoltaic parameters. This led to the development of an arrow-chart approach, consisting of five photovoltaic parameters (Voc, Isc, Rch, FF and ωc), for identifying the degradation mechanisms from the I-V and I-S measurements. In addition, an improved arrow-chart can be constructed using the newly proposed indicators (Isc/Iph, Voc/VEG, Im/Iph, and Vm/Voc) with an additional benefit of offering clear insights into the photovoltaic processes and underlying losses of solar cells. Furthermore, this work has led to the development of a novel method that overcomes the scattering problem in the I-S measurements, enabling reliable parameter extraction from severely scattered I-S plots. The results of this project also show that the I-S technique is more sensitive than the I-V measurement in detecting minor damages in the solar cells.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Engineering
Uncontrolled Keywords:	1. Solar cell characterisation 2. I-V measurement 3. Impedance spectroscopy 4. Photovoltaic parameter extraction 5. Silicon solar cells 6. Equivalent circuit analysis 7. I-S scattering 8. Broken contact fingers 9. Surface scratching 10. Heat treatment 11. Partial shading
Date of First Compliant Deposit:	14 September 2026
Last Modified:	15 Sep 2026 14:38
URI:	https://orca.cardiff.ac.uk/id/eprint/189178

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