Temperature dependence of light-enhanced series resistance, fill factor and efficiency of a-Si:H/c-Si heterojunction solar cells

The temperature dependence of the silicon hetero junction solar cell (HJT) performance is investigated using AFORS-HET simulations. It is shown that the enhancement of the cell series resistance under illumination, linked to hole reflection at the thermionic emission barrier at the a-Si:H/c-Si hetero interface, is more pronounced at low temperature which may result in the collapse of the cell fill factor, current and efficiency. The cell fill factor and efficiency increase as the temperature increases, reach a peak value and exhibit a plateau 20-30 degrees wide close to room temperature. Such a plateau extends and shifts towards lower temperature as the doping level in a-Si:H(p) increases. At higher temperature the thermionic emission barrier has negligible impact on the cell performance, but the cell efficiency decays driven by the decay of the open circuit voltage due to the rise in the cell thermal (dark) current. The results indicate the HJT cells are very suitable for deployment in areas with hot and warm weather throughout the whole year, and not recommended for deployment in regions with long periods of cold weather.