Spectrally Shaped Supercontinuum for Advanced Solar Cell Characterization

Very recently it has been demonstrated that the special characteristics of supercontinuum lasers allow for a virtually perfect imitation of standard solar spectra. As this eventually makes any spectral mismatch correction redundant, supercontinuum sources are a promising tool for solar cell characterization. This paper contributes to their further establishment in solar cell characterization in two ways: firstly, we will present a differential approach for fast and precise short circuit current measurements by chopped and spectrally shaped supercontinuum radiation. Thereby we overcome the current drawback of limited supercontinuum output power presently impeding their application in large area solar simulators. Secondly, we will assess their potential by comparing spectral mismatch correction factors of shaped supercontinuum radiation to those of state-of-the-art solar simulators for a variety of solar cells. By a Random Walk Monte Carlo method we retrieve the uncertainties of these spectral mismatches and demonstrate that imitating the moving average of a standard spectrum might yield lower measurement uncertainties as its perfect replication. Moreover, the simulations will emphasize that, even in case of a perfect replication of standard spectra, usage of spectrally well matched reference cell remains important for achieving lowest measurement uncertainties. Finally, we will present first experimental short circuit current measurements of Silicon solar cells conducted with the supercontinuum differential approach.