Impurity Photovoltaic Effect in Multijunction Solar Cells

A study has been carried out to investigate the Impurity Photovoltaic (IPV) effect on the performance of a double junction solar cell, which is yet, to the best of the authors’ knowledge, the first attempt at incorporating IPV effect in multijunction solar cell. In this work, impurity has been introduced in a double junction solar cell - separately and simultaneously in the two sub-cells which have been found to improve the cell performance. However, the effect of impurity becomes prominent when it is applied to the sub-cell with lower current. Furthermore, impact of impurity concentration has been obtained on short-circuit current density, open-circuit voltage and overall efficiency which have been explained through compensation by deep-level impurity dopant, conversion of conductivity type, carrier lifetime and total equilibrium carrier density. This improvement demonstrates the potential of the combination of IPV effect in multijunction solar cell.