Blancon, J-C. B
Even, J. E.
Layered perovskite materials with excellent opto-electronic properties offer great promise as photovoltaic absorbing layer with long term stability against environmental conditions and constant illumination. The planner structured solar cell has achieved >12% efficiency, meanwhile the unique quantum confined structure opens up new opportunity for fundamental study as well as other applications such as light emitting diodes, detection etc. However, the working principle of the layered perovskite solar cell is not well understood. In this study, we aim to understand the device properties during solar cell operation, with varying light intensity, temperature and field dependence from current-voltage characteristics. We found the charge carrier extraction relies on the device built-in potential under illumination. Moreover, there is a co-existence of exciton and free carrier during charge extraction, which is highly field dependent for thicker layers and temperature dependent. Our study shows that in order to further improve the device efficiency of layered perovskite solar cell, the exciton recombination has to be greatly suppressed by material structural design or increase the number of interfaces for efficient charge separation.