Achieving High Open‐Circuit Voltage for p‐i‐n Perovskite Solar Cells Via Anode Contact Engineering

Abstract

With photocurrents in perovskite solar cells close to their practical limit, it is imperative to improve their open‐circuit voltage to go beyond a loss‐in‐potential less than 100 mV. However, state‐of‐the‐art p‐i‐n perovskite solar cells are reported with a Voc of around 1.1–1.5 V, limiting their efficiency improvement. Herein, the authors demonstrate that the Voc of p‐i‐n perovskite solar cells can be successfully improved via anode contact engineering. First of all, by introducing a partially oxidized nickel layer, the authors are able to remove the potential barrier for hole transport and enhance the crystallinity of the hole transporting layer, both of which are believed to contribute to the Voc and FF improvement. Furthermore, by separating the inorganic NiMgOx hole transporting layer from the perovskite absorbing layer with a poly(4‐vinylpyridine) (PVP) insulating layer, the interfacial recombination could be effectively suppressed, the Voc climbs to an impressive value of 1.15 V along with a power conversion efficiency of 19.3%. Finally, a substrate‐type perovskite solar cell is fabricated with an extremely high Voc of 1.18 V, representing a very low voltage deficit in the p‐i‐n perovskite solar cells. Our works provide an avenue for further reducing the loss‐in‐potential of perovskite solar cells.