A Universal P-Type Heterointerface for Inverted Perovskite Solar Cells

Inverted perovskite solar cells with self-assembled monolayers (SAMs) have attracted extensive attention due to their high efficiency and long-term operational stability. However, the hole extraction at the SAMs/perovskite interface is generally less efficient with respect to the electron extraction. Here, we report the construction of a universal p-type heterointerface between SAMs and perovskite with heterocyclic dipolar compounds imidazole hydroiodide (ImHI). We found that the strong interaction by hydrogen bonds together with formative dipole layer were observed between ImHI and perovskite. This allows more p-type contacts with relatively small energy barriers at SAMs/perovskite heterointerfaces by downshifting the Fermi level, reducing the energy mismatch and facilitating the hole extraction. The p-type contact enhancement was further confirmed by a series of SAMs at the perovskite buried interface. As a result, a best-performing solar cell with a power conversion efficiency of 26.05% was achieved, with maintaining 96% of the initial efficiency for 2000 h under nitrogen-filled glove box, 94% of the initial efficiency for 800 h at 55 °C/55% RH, and 86% of the initial efficiency for 1000 h under continuous light stress at maximum power point.