Synergistic Engineering of Natural Carnitine Molecules Allowing for Efficient and Stable Inverted Perovskite Solar Cells.

Efficient control of the perovskite crystallization and passivation of the defects at the surface and grain boundaries of perovskite films have turned into the most important strategies to restrain charge recombination toward high-performance and long-term stability of perovskite solar cells (PSCs). In this paper, we employed a small amount of natural vitamin B (carnitine) with dual functional groups in the MAPbI precursor solution to simultaneously passivate the positive- and negative-charged ionic defects, which would be beneficial for charge transport in the PSCs. In addition, such methodology can efficiently ameliorate crystallinity with texture, better film morphology, high surface coverage, and longer charge carrier lifetime, as well as induce preferable energy level alignment. Benefiting from these advantages, the power conversion efficiency of PSCs significantly increases from 16.43 to 20.12% along with not only a higher open-circuit voltage of 1.12 V but also an outstanding fill factor of 82.78%.