Self-assembled monolayer for both metal-oxide contacts: A universal passivation strategy

Lauryna Monika Svirskaite^a, Tadas Malinauskas^a

^aDepartment of Organic Chemistry, Kaunas University of Technology, Kaunas LT-50254, Lithuania.

Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV26)

Uppsala, Sweden, 2026 May 18th - 20th

Organizers: Gerrit Boschloo, Ellen Moons, Feng Gao and Anders Hagfeldt

Poster, Lauryna Monika Svirskaite, 219
Publication date: 11th March 2026

The performance of perovskite solar cells (PSCs) is strongly influenced by defect density at the metal oxide/perovskite heterojunction interface, where external or intrinsic imperfections such as hydroxyl groups, metal-dangling bonds, or oxygen vacancies cause localized trap states [1-2]. These defects hinder favorable energy level alignment for charge transport and increase non-radiative recombination at the metal oxide/perovskite interface, leading to losses in open-circuit voltage (V_oc) and fill factor (FF) in the devices [2,3]. The noticeable result can be directly achieved via surface modification strategy using small organic molecules containing specific functional groups [4]. Introduction of self-assembled monolayers (SAMs) with strong bonding strength enables coordination with the surface non-bonded atoms or surface dangling bonds thus improving metal oxide/perovskite contact interfacial properties [4]. Various of n-type SAM modifiers including benzoic acid and its derivatives [5-7], perylene diimides [8,9], silanes [10-12], fullerene SAMs [13-16], and amino-functionalized molecules have demonstrated enhancements in device performance. Up to now, C₆₀-SAM have shown outstanding success in improvements of photovoltaic performance, leading a PCE of 27.1 % in perovskite/silicon tandem solar cells [15]. Despite these advances, fullerene derivatives are not the most cost-effective ones; also, they involve complicated synthesis and limited solubility. Therefore, the development of cost-effective alternative especially universal modifiers for metal-oxides is still promising direction for advancing PSC technology.

In this research, benzo[c][1,2,5]thiadiazole-based materials were investigated as charge selective monolayers for modification of conventional metal oxide SnO₂ and NiO_x layers in n-i-p and p-i-n architecture perovskite solar cells, respectively.

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