Triple Interface Passivation Strategy Enabled Efficient and Stable Inverted Perovskite Solar Cells

In this work, we propose a triple passivation of the two in-between surfaces of the hole transport layer (HTL) and perovskite. The inorganic salt of potassium thiocyanate (KSCN) is introduced to simultaneously crosslink NiO x HTL and methylammonium lead iodide (MAPbI 3 ), which can significantly improve both device performances and stability. In addition to potassium passivation, the thiocyanate shows two good passivation effects on perovskite and NiO x to achieve the triple passivation. The strong Ni-N bonding exhibits strong polar covalent bond properties to make the electron deviate from the Ni side. Meanwhile, the strong electrostatic force between S and Pb in MAPbI 3 makes the Pb atomic layer closer to perovskite to restrain the I atom. Meanwhile, the KSCN modification lead to better valence band alignment. Eventually, the KSCN meditated PSCs exhibit both high efficiency of 21.23% with open-circuit voltage of 1.14 V and 6-fold improvement of operational stability.