Lithium and Silver Co-Doped Nickel Oxide Hole-Transporting Layer Boosting the Efficiency and Stability of Inverted Planar Perovskite Solar Cells

In this work, a lithium and silver co-doping strategy has been successfully implied to prepare NiO x films for high performance inverted planar perovskite solar cells (PSCs). Compared to the pristine and single-doped NiO x, the Li and Ag co-doping approach exhibits the synergistic effect and can endow NiO x films with higher electrical conductivity, higher hole mobility and better interface energy band alignment with perovskite active layers. Moreover, the perovskite film with enhanced crystallinity can be obtained induced by the Li,Ag:NiO x film. The PSC with Li,Ag:NiO x HTL shows a high power conversion efficiency (PCE) up to 19.24% and less hysteresis effect, which outperforms the devices with the pristine NiO x or single-doped NiO x HTLs. Meanwhile, the Li,Ag:NiO x device can retain 95% of its initial PCE after storage at the relative humidity of 30 ± 2% in 30 days without encapsulation. Our work demonstrates that lithium and silver co-doping is a promising route for realizing efficient p-type NiO x HTL, which provides a simple way to boost the efficient and stable of inverted planar PSCs.