Abstract
Compositional heterogeneity in halide perovskite materials often leads to undesired physiochemical properties of the materials that hampers device efficiency and stability. In a perovskite film prepared via conventional 2-step method, we find excess PbI2 are prone to locate at surface and buried interfaces, resulting in negative-type self-doping. To tailor this band alignment unfavored for p-i-n devices, we pre-deposited pyrrolidinium hydroiodide to react with residual PbI2 at buried interface. It not only de-dopes the perovskite to obtain the desired band alignment, but also passivates negative-type defects, which improves the device efficiency and stability. Consequently, the target planar p-i-n PSCs achieve an efficiency of 24.5 % (certified 23.2 %) and a remarkable photostability with 13 % efficiency decline for 2800 h under 1-Sun white LED illumination. It is so far among the highest-efficiency p-i-n PSCs via 2-step fabrication. Therefore, we suggest an interface de-doping strategy to fabricate highly efficient and stable PSCs.
Published Version
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