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2011
Conference Paper
Titel
From Injection Dependent Lifetime to Solar Cell Efficiency
Abstract
In this work we analyze the solar cell efficiency limitations of multicrystalline material due to bulk recombination. We measure, spatially resolved, the injection dependent bulk lifetime of a surface passivated wafer and combine that information with a simple cell simulation. Hence, we can calculate the open-circuit voltage, the short-circuit current and the fill factor limit for every image point. To attain global values we discuss the effect of the emitter on the excess carrier distribution with Sentaurus Device and Spice network simulations. For comparison to solar cells, we analyze wafers that have undergone the relevant high temperature steps of a solar cell process. The calculated global values match very well to measured values on finished solar cells from neighboring wafers. With this procedure we could observe severe losses in short-circuit current in dislocated areas on the wafer and also show why the fill factor of multicrystalline cells is limited by the bulk material.
Author(s)