A new approach for the performance evaluation of solar cells under realistic reporting conditions

An algorithm was developed which permits the determination of the realistic reporting conditions (RRC) efficiency of solar cells without the need for long-term outdoor measurements of the test objects. For Freiburg (48°N), the year 1986, and a set of three specific sample cells (mono-Si being rather poor), the influence of irradiance, temperature, and solar spectral distribution under RRC on the cell efficiencies was determined. On a yearly basis the RRC efficiency is lower than standard reporting conditions (SRC) efficiency by 7.6%, 8.5% and 9.2% for mono-Si, multi-Si, and GaAs, respectively. The highest monthly deviation is -13.3% in July for GaAs. The strongest reduction comes from irradiance (4.2%-6.3% on a yearly basis) and temperature (3.8%-4.1%), the latter being strongly modulated over the course of a year. The largest spectral effect on a yearly basis was +1.1% and on a monthly basis 3.4% in February for the multi-Si sample