Identifying the Recombination Zone in Perovskite Solar Cells

In perovskite solar cells, the loss of photo-generated charge-carriers due to recombination is widely reported. In this work, we identified the recombination zone in a perovskite solar cell by analyzing the spatial distribution of photo-generated electron- and hole-density. It is observed that the location of the recombination zone is dependent on the pre-bias voltage applied to the device prior to illumination. That is, it is located within the perovskite layer for the condition in which zero pre-bias voltage is applied prior to illumination. However, it shifts towards the interfacial layer when a pre-bias of 1.0 V is applied prior to illumination. This pre-bias effect may be utilized to limit the recombination of charge-carriers from perovskite to the interfacial layer. Thereby, reducing the loss of photo-generated charge-carriers in the perovskite layer.