The impact of C60-self-assembled monolayer electron-transport layers in negative–intrinsic–positive perovskite solar cells

Journal article : Letter

We investigate the impact of employing fullerene self-assembled monolayers (SAMs) in conjunction with SnO₂ electron-transport layers (ETLs) in negative–intrinsic–positive (n–i–p) perovskite solar cells. We compare the efficacy of the fullerene-SAM surface-binding group—carboxylic or phosphonic acid—on the passivation, charge transport, and energetics of the modified-SnO₂ surface. Planar n–i–p perovskite solar cells with these SAM-modified SnO₂ exhibit significantly reduced hysteresis, and the steady-state maximum power point tracked efficiencies (η_MPP) of the devices improved from an average of 18.6–20.0% comparing devices with neat SnO₂ to the C₆₀-PA SAM inclusion, respectively. While C₆₀-PA SAM improved the initial solar cell efficiency, this benefit was not maintained during light exposure at elevated temperatures as the fullerene SAM weakened adhesion at the perovskite/metal oxide interface in the aged devices. These results highlight the importance of improving the mechanical robustness of perovskite/charge-transport layer interfaces under operational aging conditions.

Authors: Zhou, S; Gregori, L; Seo, S; Dasari, RR; Lee, JE

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: ACS Energy Letters
• Volume: 11
• Issue: 9
• Pages: 6177–6186
• Publication date: 2026-08-24
• Acceptance date: 2026-06-22
• DOI: 10.1021/acsenergylett.6c01485
• EISSN: 2380-8195
• Language: English
• Subtype: Letter