Double-sided surface passivation of 3D perovskite film for high-efficiency mixed-dimensional perovskite solar cells

Md Arafat Mahmud, The Duong, Yanting Yin, Huyen T. Pham, Daniel Walter, Jun Peng, Yiliang Wu, Li Li, Heping Shen, Nandi Wu, Naeimeh Mozaffari, Gunther Andersson, Kylie R. Catchpole, Klaus J. Weber, Thomas P. White

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140 Citations (Scopus)


Defect-mediated carrier recombination at the interfaces between perovskite and neighboring charge transport layers limits the efficiency of most state-of-the-art perovskite solar cells. Passivation of interfacial defects is thus essential for attaining cell efficiencies close to the theoretical limit. In this work, a novel double-sided passivation of 3D perovskite films is demonstrated with thin surface layers of bulky organic cation–based halide compound forming 2D layered perovskite. Highly efficient (22.77%) mixed-dimensional perovskite devices with a remarkable open-circuit voltage of 1.2 V are reported for a perovskite film having an optical bandgap of ≈1.6 eV. Using a combination of experimental and numerical analyses, it is shown that the double-sided surface layers provide effective defect passivation at both the electron and hole transport layer interfaces, suppressing surface recombination on both sides of the active layer. Despite the semi-insulating nature of the passivation layers, an increase in the fill factor of optimized cells is observed. The efficient carrier extraction is explained by incomplete surface coverage of the 2D perovskite layer, allowing charge transport through localized unpassivated regions, similar to tunnel-oxide passivation layers used in silicon photovoltaics. Optimization of the defect passivation properties of these films has the potential to further increase cell efficiencies.

Original languageEnglish
Article number1907962
Number of pages11
JournalAdvanced Functional Materials
Issue number7
Publication statusPublished - 12 Feb 2020
Externally publishedYes


  • mixed-dimensional perovskite
  • passivation
  • solar cells
  • surface bandgap widening

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