All-inorganic halide perovskites for air-processed "n-i-p" monolithic perovskite/organic hybrid tandem solar cells exceeding 23% efficiency

All-perovskite tandem solar cells recently surpassed 26% power conversion efficiency using a Sn(ii)-based halide perovskite rear subcell, which introduces several issues related to the chemical instability and the effectiveness of common, inexpensive interconnecting layers. Adopting an all-organic blend as the rear subcell, we report here efficient "n-i-p" monolithic hybrid tandem solar cells based on metal-ion doped all-inorganic gamma-CsPb(I1-xBrx)(3), perovskite front subcells and a solution-processed ternary organic blend rear subcell. Dynamic hot-air deposition of the perovskite films allowed devices to be made and tested entirely in the open air, and passivation of the perovskite layer and the zinc oxide electron selection layer suppressed interfacial recombination and minimized the open-circuit voltage loss (0.025 V). Our devices achieved a maximum efficiency of 23.07% with an open-circuit voltage of 2.110 V, retaining >90% of the initial efficiency over 600 h at maximum power tracking under continuous illumination.