Critical role of dopant in NiOx hole transport layer for mitigating redox reactivity at NiOx/absorber interface in mixed cation perovskite solar cells

V-dopant’s hard acid electronic nature reduces the Lewis acid-base reaction at NiO x /perovskite interface. This work shows that the redox process mediated by Ni 3+ ions is inhibited even when the Ni 3+ /Ni 2+ ratio rises with doping.