Impact of solar simulator spectrum on multi-junction solar cell measurement

Accurate laboratory measurement of the IV parameters of multi-junction (MJ) solar cells is highly dependent on the incident spectrum. This paper examines the influence of simulator spectrum on MJ solar cell measurements through the use of a multi-zone solar simulator capable of varying light output on each MJ subcell independently. It is shown through solar simulator spectrum offset that standard characterization methodology may result in significant error in IV parameter measurement resulting in over or underestimation of cell performance.

I. Introduction

The measurement of IV parameters of solar cells is generally performed with a solar simulator that can produce an output spectrum closely matching the desired illumination environment, typically AMO or AM1.5. The performance of multi-junction (MJ) cells is highly impacted by the incident spectrum [1] and as a result, accurately measuring MJ cells requires spectral adjustability in order for each subcell to generate the same photocurrent as it would when exposed to the reference spectrum. This is typically done with a multisource simulator capable of independently adjusted output in different spectral bands through controllable light sources, filters, or a combination of the two.