Spectral responsivity of WPVS reference cells under varied temperatures and its influence on performance measurements beyond STC

The authors present the results of a study which investigates the temperature dependence of the spectral responsivity of WPVS reference cells and its influence on measurement uncertainties for performance measurements beyond standard test conditions (STC). Five crystalline unfiltered reference cells from three different manufacturers were spectrally characterized at different temperatures. The authors calculated the temperature coefficient of the reference cells at different wavelengths and temperature ranges and showed significant deviations from the temperature coefficient of the calibration certificate. However, it is shown that the tested commercial reference cells have a non-linear behavior for a temperature range of 25 to 60°C and therefore they cannot be used for measurements at high temperatures e.g. outdoor applications or temperature coefficient measurements. The report demonstrates how this affects performance measurements above 25°C.