Successive surface engineering of TiO2 compact layers via dual modification of fullerene derivatives affording hysteresis-suppressed high-performance perovskite solar cells

摘要: Interfacial engineering is critical for highly efficient charge carrier transport in perovskite solar cells (PSCs). Herein, we developed a new method, called successive surface engineering, that affords PSCs with enhanced efficiency and dramatically suppressed current–voltage hysteresis. Upon modifying the TiO2 compact layer, which commonly used as an electron layer (ETL) regular-structure (n–i–p) planar heterojunction (PHJ) PSCs, by successively incorporating [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) ethanolamine (ETA)-functionalized fullerene (C60-ETA) synthesized facilely via one-pot nucleophilic addition reaction, average power conversion (PCE) of CH3NH3PbI3-based PHJ-PSC devices increased from 13.00% to 16.31%; best PCE attained was 18.49%, which, our knowledge, represents highest reported date PHJ-PSCs based on fullerene-modified interlayers. In contrast, single PC61BM or C60-ETA alone results only negligible changes PCE, revealing synergistic effect these two derivatives: can passivate traps surface, while subsequent not improves wettability film ETL but also facilitates across interface between ETL. The structural morphological characterizations show following dual modification C60-ETA, both coverage crystallinity CH3NH3PbI3 are improved. Steady-state photoluminescence decay electrochemical impedance spectroscopic studies manifest substantially extraction suppresses recombination. As consequence, this leads obvious increase short-circuit current density (Jsc), contributes primarily enhancement. Additionally, because may induce passivation remarkably, hysteresis response modification.