A new tool for multijunction cell diagnostics-QE measurements under AM1 bias light

The authors attempt to obtain a relatively simple diagnostic tool that can be used to optimize the efficiency of multijunction solar cells. This measurement should be able to pinpoint which sub-cell most needs improvement. In this report, they explore such a tool: the quantum efficiency at the maximum power point under AM1 light (AM1QE). They demonstrate the application of AM1QE-based guidelines with AMPS computer program simulations and show that the most substantial improvement from sub-cell thickness adjustments comes from the sub-cell which causes a peak in the AM1QE. They also show that this proposed AM1QE quantum efficiency measurement for multijunctions is a much more sensitive monitor of changes in a multijunction than the so-called color light bias quantum efficiency measurement