Electrochemical quantification of phosphonic acid passivated surface sites of NiOxfor perovskite solar cells

Xie C, Minh DN, Kret R, Hoffman J, Rillera AP, Wilks RG, Félix R, Anderson MA, Frisch J, Bär M, Migliozzi M, Louks A, Schutt K, Wheeler LM, Berry JJ, Zhu K, Kerner RA, Luther JM (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Energy and Environmental Science Royal Society of Chemistry

DOI: 10.1039/d5ee05065k

Abstract

Nickel oxide (NiOx) is among the few p-type metal oxide semiconductors considered a strong candidate for hole transport layers in halide perovskite solar cells (PSCs). However, its reactivity with perovskite ions poses significant challenges to achieving high efficiency and long-term stability. Here, we investigate passivation of detrimental reactive surface sites on NiOx by carbazole phosphonic acids. We leverage electrochemical cyclic voltammetry (CV) of NiOx electrodes as a proxy measure for the redox activity that afflicts PSCs. From the CVs, we derive a metric, N (units cm−2), that relates to the number of redox active sites on NiOx surfaces. We observe a statistically significant negative correlation between PSC efficiency and N-value that indicates PSCs are more efficient on NiOx with lower electrochemical reactivity. The new mechanistic insight into NiOx passivation demonstrates it requires a reducing agent and Brønsted acid combination, providing a broadly applicable approach for evaluating and enhancing the stability and performance of NiOx-based interfaces in photovoltaics.

Authors with CRIS profile

Marcus Bär

Involved external institutions

Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) DE Germany (DE) National Laboratory of the Rockies (NLR) US United States (USA) (US)

How to cite

APA:

Xie, C., Minh, D.N., Kret, R., Hoffman, J., Rillera, A.P., Wilks, R.G.,... Luther, J.M. (2026). Electrochemical quantification of phosphonic acid passivated surface sites of NiOxfor perovskite solar cells. Energy and Environmental Science. https://doi.org/10.1039/d5ee05065k

MLA:

Xie, Chenchao, et al. "Electrochemical quantification of phosphonic acid passivated surface sites of NiOxfor perovskite solar cells." Energy and Environmental Science (2026).

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