Advanced Local Quality Assessment of Monocrystalline Silicon Solar Cell Efficiency

Abstract

Solar cells, or photovoltaic cells, are used to convert sunlight into electrical power. The defects or imperfections in silicon solar cells lower the light-current conversion and consequently also an efficiency of the device. These defects in the semiconductor structure are normally detected by electric measurements. The thermal dependency of breakdown voltage is positive and the defects can be revealed by surface inhomogenity. To ensure a higher quality of the solar cells, advanced local quality assessment is provided and experimental results of solar cell defect measurement in microscale region are presented. Using Near-field optical beam induced current and voltage method, both current and voltage in defect area were detected and individual defects were localized with higher spatial resolution. This measurement also verifies that in reverse biased electroluminescence spots the quantum efficiency is lower and so these spots affect overall quality of the cell.