On the use of I–V curves as a diagnosis tool for proper external quantum efficiency measurements of multijunction solar cells

External quantum efficiency measurement of multijunction solar cells is not an easy task. In this paper we propose to trace the I-V curve of the multijunction device under the same light bias conditions intended to be applied for the EQE measurement as an effective way to minimize artifacts and determine the optimum light and voltage bias conditions for the measurement. In this way, the analysis of the I-V curve will help to determine the proper voltage bias needed (if any), as well as to distinguish whether the external quantum efficiency measurement is being affected by shunt problems, early breakdown or luminescent coupling. This is of special relevance in order to determine the origin of the measurement artifact affecting the external quantum efficiency measurement of MJSCs.