Energetic relevance of solar spectral variation on solar cell short circuit current

The effect of variation in the spectral distribution of the insolation on the short circuit current of GaAs and monocrystalline, polycrystalline and amorphous Si solar cells is assessed using two sets of spectral data. The first is a two year segment from the five year series of global radiation spectra recorded in Freiburg, West Germany (48 degrees N); the second is a set of direct radiation spectra simulated for the whole year and this latitude with the LOWTRAN6 programme. As a basis of comparison, the I sub sc predicted with the standard SERI global radiation spectrum was taken. This was found to agree well with the results from the measured spectra on a monthly or yearly time scale for the crystalline Si cells, but to deviate by up to 6% for monthly values for GaAs, and by +-3% for yearly and up to 9% for monthly predictions for a-Si. The diffuse radiation component was found to be too large for the direct radiation data to be a useful prediction tool for the spectral dependence. ( ISE)