Influence of spectral beam splitting on the performance of polycrystalline silicon PV cells

Abstract

This report determines the influence of spectral beam splitting on the temperature, maximum power and efficiency of a polycrystalline silicon cell under concentrated light. The PV cell was exposed to wavelengths ranging between 450 nm – 1000 nm. It was found that spectral beam splitting results in a temperature 11 °C lower than the PV cell that was exposed to the full spectrum after one hour. Additionally, it was also found that spectral beam splitting improves the efficiency of the PV cell by 2.1% at 980 W·m-2 and cell temperature of 25 °C. A study into the effect of light intensity on the efficiency showed that the efficiency increases between 580 W·m-2 – 680 W·m-2, after which the efficiency decreases up to 1380 W·m-2. Furthermore, it was found that the reason for the decrease in the efficiency was the decrease in the fill factor which is caused by the decrease in the shunt resistance. A comparison between the PV cell under the filtered spectrum and the full spectrum, showed that the PV cell exhibits a similar trend in efficiency as light intensity increases. However, the efficiency difference is initially at approximately 3% between 580 W·m-2 and 780 W·m-2, thereafter, the efficiency difference decreases to approximately 2 %. Based on these results, it has been recommended that further research be carried out to understand how wavelengths influence the band gaps of PV cells as the light intensity increases.