Real-space distributions of electrical potential in planar and porous perovskite solar cells: Carrier separation and transport

We study the carrier transport and separation in planar and porous PS devices, which is one of the most fundamental operation mechanisms of solar cells, by profiling the electrical potential across the devices. We found that the PV devices work by p-n junction at the TiO₂/PS interface for the both device structures. Combining the potential profiling results with the solar cell performance parameters taken on the optimized and thickened devices, we found that mobility is the main factor limiting the device performance. Improving the mobility both within grains and across grain boundaries (or enlarging the grain size) are expected to significantly improve the device efficiency.