Irradiance Dependent Temperature Coefficients for MC Solar Cells from Elkem Solar Grade Silicon in Comparison with Reference Polysilicon

AbstractAn increase in sun intensity enhances the output power of the solar cells, but at the same time the rise of cell temperature affects its electrical performance negatively. The present authors have made a comparative study on temperature coefficients at various irradiances of multicrystalline solar cells made from the standard Siemens process and from material produced by a metallurgical route – the Elkem Solar Silicon (ESS®) process. Such temperature coefficients measured while exposed to various irradiance levels are essential to build a better understanding and prediction of field performance of solar cells manufactured from various feedstock types. In the current experiment, the current-voltages characteristics are measured for all solar cells by exposing them to an AM 1.5 spectrum from a AAA sun simulator in order to calculate the temperature coefficients. Electroluminescence (EL) images in forward bias mode are also provided. It was observed that ESS™ solar cells show significantly better temperature coefficients for current, efficiency and fill factor compared to similar cells from polysilicon at all incident irradiances. Such better temperature coefficients have also been reported previously from field measurements [1]