Defection-stripping and balanced carrier extraction strategy enables efficient and ultra-low hysteresis of inverted inorganic perovskite solar cells.

A facile post-treatment method named defection-stripping and balanced carrier extraction strategy was used to induce p to n-type transition at CsPbI 2.85 Br 0.15 surface. A high efficiency of over 20.30% and ultra-low hysteresis at record level were achieved in inverted inorganic perovskite solar cells. [Display omitted] • Defection-stripping strategy was used to induce p to n-type transition. • Aminoguanidine hydrochloride (AH) achieves the dual function of surface reconstruction and in-situ passivation. • Inverted devices achieve above 20.30% efficiency and ultra-low hysteresis. Inorganic perovskite solar cells (IPSCs) generally face severe hysteresis phenomenon, which limits their application in tandem solar cells (TSCs). Here we introduced a defect-stripping and balanced carrier extraction strategy to mitigate the hysteresis phenomenon. By applying dynamical spins of aminoguanidine hydrochloride (AH) to the upper surface of the inorganic perovskite, the AH material was distributed in a gradient near the surface, leading to a more appropriate level matching between CsPbI 2.85 Br 0.15 and the PC 61 BM as well as reduced non-radiative recombination. However, the modification material penetrates into the interior of the inorganic perovskite and enhances the effective extraction of electrons, leading to non-equilibrium carrier extraction. The power conversion efficiency (PCE) is then further increased to 20.30% by increasing the concentration of the NiO x hole transport layer (HTL), achieving a record ultra-low hysteresis. [ABSTRACT FROM AUTHOR]