Ultrafast carrier dynamics in high-performance α-bis-PCBM doped organic-inorganic hybrid perovskite solar cell

A fullerene derivative, alpha-bis-PCBM (bis-phenyl-C-61-butyric acid methyl ester), is introduced as a dopant in the methylammonium lead iodide (MAPbI(3)) perovskite active layer to form a perovskite solar cell, demonstrating increased power conversion efficiency by 12% compared to neat MAPbI(3) -based devices, reduced photocurrent hysteresis and long-term stability in an unpacked environment. By measuring the ultrafast carrier dynamics of neat MAPbI(3), MAPbI(3): PCBM, MAPbI(3): alpha-bis-PCBM active layers with transient absorption spectroscopy, we found that the alpha-bis-PCBM as the electron acceptor in perovskite active layer leads to reduced trap-assisted recombination and effective charge transfer into the electron acceptor. The carrier kinetics in the MAPbI(3): alpha-bis-PCBM active layer is not seriously deteriorated during the exposure in atmospheric environment. High performance in perovskite solar cells well correlates improved microscopic ultrafast carrier dynamics, providing a deep insight to uncover the functioning of hybrid solar cells.