AM0 Irradiance Conditions for Electrical Performance Measurements of Triple Junction Cells at Extreme Low and High Temperatures

For accurate electric performance measurements of multi-junction solar cells at AM0 illumination conditions under simulated light, the most important parameter to be controlled is the effective irradiance of their individual sub-cells. The AM0 equivalent irradiance conditions once established on a solar simulator at standard cell temperature, i.e. 25°C, might not be fulfilled at certain temperatures when performing electrical measurements on triple junction (3J) GaInP2/ InGaAs/Ge space cells in a wide cell temperature range from -175°C to +140°C, and therefore might entail erroneous electrical cell parameter results. In a study on different solar simulators at INTA-Spasolab the effective irradiance under such AM0 illumination conditions are determined for 3J solar cells at different temperatures. The solar simulator spectra are analyzed by determining those spectral zones affecting the most to required AM0 illumination conditions at low and high temperatures. This analysis demonstrates that the influences of the respective solar simulator spectrum are more associated with specific wavelength zones rather than the solar simulator classification in fixed wavelength bins.