Measurement uncertainties of the calibration of multi-junction solar cells

Measurement uncertainties in the calibration of multijunction (MJ) cells are investigated. The focus is placed on the uncertainties originating from the main error sources when calibrating solar cells. These are the simulator spectrum and the spectral response measurement. Both uncertainties lead to an increase in the uncertainty of the photocurrents of the subcells. The correlation between the uncertainties of the cell parameters resulting from the above mentioned error sources is addressed. It will be shown that the correlation between the uncertainties of the cell parameters in a MJ cell differs from that in a single-junction (SJ) cell. The spectrometric characterization technique is used in a slightly modified way to reveal the dependencies of the different cell parameters on the uncertainties of the photocurrent in the subcells. For a triple-junction cell an expanded uncertainty of 2.4 % in power with a 95 % confidence was determined.