Hole-transfer cascade-engineered donor polymer for unencapsulated perovskite solar cells with improved moisture stability

초록

Moisture reactivity of metal halide perovskites remains a barrier to commercializing perovskite solar cells because it necessitates encapsulation and increases manufacturing complexity and cost. Hybrid perovskite/organic architectures that incorporate organic semiconductor layers offer a promising solution to improve moisture resistance while enhancing near-infrared photon harvesting. However, direct integration often causes energy-level misalignment and charge accumulation, limiting efficiency and stability. Here we investigate charge accumulation mechanisms and engineer the electronic structure of these hybrid solar cells using multiphysics modelling. We present a cascade hole-transfer strategy that employs an electron-donating polymer with a deep highest-occupied molecular orbital, which suppresses charge recombination in the perovskite bulk and at interfaces. Solar cells achieve a power conversion efficiency of 27.18% (certified 26.71%) and maintain 95% of their initial efficiency after 3,000 h under damp-heat conditions (ISOS D-3 protocol, 85 degrees C, 85% RH).

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