Effect of Luminescent Coupling on the Optimal Design of Multijunction Solar Cells

We analyze the implications of luminescent coupling on multijunction cell design and performance, using a recently developed formalism that uses the measured luminescent coupling parameters as inputs to an analytical model of the full current-voltage (J-V) characteristic of the cell. This calculation of the full J-V curve allows the determination of the cell open-circuit voltage, short-circuit current, fill factor, and efficiency in the presence of luminescent coupling. We show that luminescent coupling affects critical aspects of the cell design that include the optimal junction thicknesses and bandgaps, and affects the dependence of the cell performance on the spectral content of the light illuminating it.