Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector
Molecular Engineering of Electron Transport Layers via Steric Hindrance and Chelation Toward Stable Inverted Perovskite Solar Cells
A synergistic strategy combining steric hindrance modulation and chelation group incorporation is developed for the electron transport layer (ETL). This approach averts thermal aggregation through steric shielding, reinforces perovskite/ETL interfaces by passivating Pb?I dipoles and Pb2+ defects, and promotes uniform SnOx deposition via enhanced hydrophilicity, thereby suppressing non?radiative recombination. The resulting perovskite solar cells achieve record efficiencies across a wide range of bandgaps, with superior thermal and light stability.ABSTRACTFullerene derivatives, such as C60 and PCBM, are widely used as electron transport layers (ETLs) in inverted perovskite solar cells (PSCs) due to their high electron mobility and well?aligned energy levels. However, their poor photo?thermal stability and weak interactions with perovskite limit further progress. To address these challenges, we develop a novel fullerene derivative, 2Py, as the ETL for inverted PSCs via a synergistic strategy combining steric hindrance modulation and chelation group incorporation. This molecule delivers three key benefits: moderate steric hindrance inhibits ETL aggregation during thermal aging; chelation groups enhance interfacial interactions with the perovskite layer; and improved hydrophilicity promotes uniform SnOx film growth via atomic layer deposition (ALD). 2Py ETL enables an efficiency of 26.07% for inverted PSCs based on a 1.55?eV bandgap. Wide?bandgap (1.80 eV) and narrow?bandgap (1.25 eV) PSCs achieve efficiencies of 19.94% and 24.06%, respectively. Notably, these devices demonstrate exceptional photo?thermal stability, achieving T99 >1080 h under 85°C heating and T99 >1250 h under maximum power point tracking at 45°C, outperforming PCBM?based devices. This molecular design strategy paves new pathways for enhancing ETL performance and stability in inverted PSCs.
» Publication Date: 16/01/2026
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº 768737
