Mesoporous TiO layer suppresses ion accumulation in perovskite solar cells

Ion accumulation in perovskite solar cells can be highly suppressed by a mesoporous TiO 2 layer. This is evidenced by the decrease of the ion-related electrostatic potential with increasing the thickness of the mesoporous layer, accounted for by the electron population in the shallow trap states of the TiO 2 nanocrystals. The TiO 2 -nanoparticle scaffold suppresses ion accumulation in mesoporous perovskite solar cells by reducing the electrostatic interaction between the conductive substrate and the perovskite active layer.