| Authors |
Zimmermann, Lea ; Petrulevičius, Julius ; Menzel, Dorothee ; Bernardes de Araujo, Wander Max ; Morita, Kazuki ; Maniyarasu, Suresh ; Simmonds, Maxim ; Salimi, Yasaman ; Kim, Dong Kuk ; Mathies, Florian ; Scheler, Florian ; Berwig, Sebastian ; Sung, Woongmo ; Nihonyanagi, Satoshi ; Mahboubi Soufiani, Arman ; Harter, Angelika ; Jankauskas, Vygintas ; Kurpiers, Jona ; Malinauskas, Tadas ; Tahara, Tahei ; Creatore, Mariadriana ; Wood, Sebastian ; Schlatmann, Rutger ; Stannowski, Bernd ; Korte, Lars ; Köhnen, Eike ; Getautis, Vytautas ; Albrecht, Steve |
| Abstract [eng] |
The fullerene C 60 is the prevalent electron transport material (ETM) in high-efficiency perovskite/silicon tandem solar cells. However, it introduces intrinsic limitations, including high interfacial non-radiative recombination losses, the formation of mechanically weak interfaces, and high parasitic absorption. Here, we report a non-fullerene ETM based on a meta -carborane core and 9-fluorenylidene malononitrile functional groups (mCB-FMN) that addresses these challenges while maintaining the processing advantages of C 60 . Thermally evaporated mCB-FMN forms uniform, conformal thin films that enable efficient electron extraction and strongly suppress interfacial non-radiative recombination losses compared to C 60 . The introduction of this novel ETM further reduces oxygen-induced degradation of the perovskite/ETM interface, improves the nucleation of the SnO x buffer layer grown by atomic layer deposition and enhances interfacial adhesion within the perovskite/ETM/SnO x stack. Its wide optical bandgap is another key advantage, as it minimizes parasitic absorption losses in tandem solar cells. Replacing C 60 with mCB-FMN in opaque p–i–n perovskite single-junction devices improves the power conversion efficiency (PCE) by 1.5% (absolute), driven by a 110 meV increase in open-circuit voltage ( V OC ). Proof-of-concept perovskite/silicon tandem integration of mCB-FMN yields a PCE of 31.3%, surpassing the C 60 -based reference by 2.4% (absolute) through simultaneous improvements in V OC and short-circuit current density. These results establish mCB-FMN as a novel non-fullerene ETM for perovskite/silicon tandem solar cells that overcomes the performance limitations of conventional C 60 and highlight carborane-based compounds as a promising new class of materials for high-efficiency perovskite photovoltaics. |
