Enhanced perovskite solar cell performance via low-temperature ALD-Al2O3 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 (Al₂O₃) 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 Al₂O₃ 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 cm²), which was a notable enhancement compared to solar cells of average power conversion efficiency (PCE) 20.33% without Al₂O₃ 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-Al₂O₃ in inverted perovskite solar cells as well as perovskite–silicon tandem solar cells.

Graphical abstract