The bias-dependence of luminescent coupling efficiency in multijunction solar cells

In this work we describe the dependence of luminescent coupling efficiency on the bias-voltage in multijunction solar cells. We combine a theoretical derivation and Sentaurus simulations to show that the luminescent coupling efficiency has a significant dependence on the bias voltage, and such dependence is mainly due to the change in the ratio between radiative and non-radiative recombination currents at different bias voltage. We further show that such change is due to the variation in the recombination rate distribution in the cell. In addition to showing the necessity of including bias-dependence in luminescent coupling modeling, this work also demonstrates the importance of including a bias-dependent luminescent coupling efficiency to accurately model multijunction solar cells.