Fast and Accurate Short-Circuit Current versus Irradiance Determination of a Spectrally Nonlinear Solar Cell Using a Spectral Shaping Setup
This work presents a fast and accurate solar cell characterization method for determining the short-circuit current ISTC under standard test conditions. Additionally, the short-circuit current versus irradiance relation is derived, including accurately and precisely measured nonlinearities. Similar to the Differential Spectral Responsivity (DSR) method, our White Light Response (WLR) method uses a differential measurement technique with lock-in amplifiers. The first derivative of the short-circuit current versus irradiance relation (AM1.5-weighted differential responsivity) is measured at many irradiance levels without additional spectral mismatch corrections and considers the AM1.5 reference solar spectral irradiance distribution. The WLR method is significantly faster than the DSR method in determining the short-circuit current and nonlinearities. The highly spectrally nonlinear rear side of a bifacial PERC solar cell was investigated. The strong influence of the number of measured AM1.5-weighted differential responsivities and interpolation procedures on the short-circuit current ISTC is demonstrated. Finally, the accuracy of the results is discussed by means of a measurement comparison with the fully spectrally resolved DSR methods at PTB and CalLab PV Cells at ISE.