Spectral response set ups allow the measurement of (absolute) spectral response and of cell reflectivity.
The spectral response of a solar cell is an important tool to analyze the underlying semiconductor parameters that govern its overall conversion efficiency.
By modeling or direct extraction of parameters from spectral response curves, diffusion lengths and surface recombination velocities can be extracted. Also, the spectral response can give information on conduction processes, e.g. for field assisted carrier collection in concentrator solar cells.
The corresponding data, on the other hand, is only relevant if data is taken at the appropriate light level that is intended for the daily operation of the solar cell.
This is due to the fact that recombination centers may be filled at the carrier levels present in outdoor operation. But measuring the spectral response at lower light levels, on the other hand, will predict erroneous values of spectral response e.g. due to carrier losses in exactly these recombination centers.
Presently, the spectral response, even of concentrator solar cells, is largely measured at carrier injection Levels much lower up to close to the one sun intensity.
To allow the analysis of (concentrator) solar cells at high carrier injection levels, Optosolar has designed spectral response measurement systems for the illumination of solar cells with very intense monochromatic light.