Stacchini, V.; Rastgoo, M.; Marcinskas, M.; Frasca, C.; Morita, K.; Frohloff, L.; Treglia, A.; Gries, T.W.; Karalis, O.; Getautis, V.; Ruske, F.; Petrozza, A.; Koch, N.; Hempel, H.; Malinauskas, T.; Abate, A.; Musiienko, A.: Phenothiazine-Based Self-Assembled Monolayer with Thiophene Head Groups Minimizes Buried Interface Losses in Tin Perovskite Solar Cells. Advanced Energy Materials 15 (2025), p. 2500841/1-8
10.1002/aenm.202500841
Open Access Version
Abstract:
Self-assembled monolayers (SAMs) have revolutionized the fabrication of lead-based perovskite solar cells, but they still remain underexplored in tin perovskite systems. To date, PEDOT remains the most effective hole-selective layer in tin perovskite solar cells (TPSCs), yet it presents challenges for both performance and stability. MeO-2PACz, the only SAM reported for tin perovskites consistently underperforms when compared to PEDOT. In this work, it is identified that MeO-2PACz's limitations stem from excessively strong interactions with the perovskite surface and poor lattice matching, which leads to inferior interface quality. To address these issues, a novel SAM-forming molecule called Th-2EPT is designed, synthesized, and characterized. Density functional theory (DFT) is used to evaluate coordination strength and lattice compatibility, complemented by electro-optical characterisation techniques that show significantly reduced interfacial recombination and improve material crystallinity in Th-2EPT/Perovskite films. With Th-2EPT, the first SAM-based tin perovskite solar cells that outperform PEDOT-based devices, delivering a power conversion efficiency (PCE) of 8.2% with a DMSO-free solvent system, are demonstrated.