Solar energy as a renewable energy source has drawn great attention over last decades due to the depletion and environmental impact of fossil fuels. Many technologies have been developed to harvest solar energy, among which solar cells are a promising technology to directly convert energy into electricity. To date, the photovoltaic market is dominated by silicon-based solar cells as they give reasonable high power conversion efficiencies. However, silicon solar cell panels are heavy, brittle and costly. Therefore, extensive research is dedicated to find alternative solar cell systems.