Power from the sun: Perovskite solar cells

We report the influence of porosity and pore size on perovskite solar cell efficiency. We demonstrate an alternative electrode synthesis route that goes beyond traditional paste processing by incorporating a second distribution of nanoparticles composed of ZnO into the TiO₂ paste. After calcination to form a mesoporous film, the ZnO nanoparticles are selectively etchable under acidic conditions to lead to additional mesorporosity in the TiO₂. These modified films exhibit increased perovskite loading for a given thickness and led to improved current densities and power conversion efficiencies. We anticipate that this additional mesoporosity control may be beneficial for numerous other applications.