Hybrid organic–inorganic perovskite materials have risen up as leading components for light harvesting applications. However, to date many questions are still open concerning the operation of perovskite solar cells (PSCs). A systematic analysis of the interplay among structural features, optoelectronic performance, and ionic movement behavior for FA0.83MA0.17Pb(I0.83Br0.17)3 PSCs is presented, which yield high power conversion efficiencies up to 20.8%.