Enhanced perovskite solar cell performance via low‐temperature ALD‐Al 2 O 3 interface modification

Inverted perovskite solar cells, which nickel oxide (NiO x ) has been widely employed as a hole transport layer, have shown promise for perovskite–silicon tandem solar cells. However, the deficient quality of perovskite/NiO x interface has constrained the performance and stability of the solar cells. In this paper, low‐temperature atomic layer deposition (ALD) was employed to prepare a nanometer aluminum oxide (Al 2 O 3 ) layer that effectively blocks carriers recombination, facilitates carriers transport by improving the valence band maximum (VBM) alignment between HTL and perovskite and enhances the morphology of self‐assembled monolayer (SAM). The interface between NiO x and perovskite was modified by the embedded Al 2 O 3 layer, achieving an open current voltage ( V oc ) of 1.19 V and a short‐circuit current density ( J sc ) of 22.98 mA cm −2 . The efficiency of the champion cell was 22.22% at 1.5 AM (0.2 cm 2 ), which was a notable enhancement compared to solar cells of average power conversion efficiency (PCE) 20.33% without Al 2 O 3 passivation layer. The passivated perovskite solar cell exhibits enhanced stability in degradation tests, retaining 85.70% of the initial PCE after storage in ambient air (40%–60% relative humidity (R.H.)) at 25 °C for 100 h. The results show the potential of low‐temperature ALD‐Al 2 O 3 in inverted perovskite solar cells as well as perovskite–silicon tandem solar cells.