Recently, the research team led by Prof. Yao Huifeng from the School of Chemistry and Chemical Engineering, SEU, in collaboration with Trina Solar, Fudan University, and other institutions, has achieved significant progress in the research of perovskite/perovskite/crystalline silicon triple-junction solar cells. The related findings were published in the top international academic journal Nature under the title “Defect passivation and optical management of triple-junction solar cells.”
Perovskite/perovskite/crystalline silicon triple-junction solar cells utilize absorber materials with different bandgaps to enable tiered utilization of the solar spectrum, offering the potential to surpass the efficiency limit of single-junction solar cells. Among them, the wide-bandgap perovskite top cell is key to achieving a high output voltage; however, issues such as surface defects and non-radiative recombination cause significant voltage losses, becoming a major bottleneck that hinders further efficiency improvement of triple-junction devices.
To address this critical challenge, the team designed and synthesized a novel interfacial passivation material, 4F-POEABr, based on molecular engineering. This molecule integrates a perfluorinated aromatic conjugated skeleton with strong electron-withdrawing capability into an ammonium salt passivation group, achieving synergistic chemical passivation and field-effect passivation — which is the core material design concept of this work. Experimental results demonstrate that 4F-POEABr can effectively reduce surface defects and non-radiative recombination in wide-bandgap perovskites, improve film uniformity, and significantly suppress halide migration and phase segregation under light illumination.
After modification with this molecule, the 1.95 eV wide-bandgap sub-cell achieved an open-circuit voltage of 1.413 V. On this basis, the collaborative team further combined optical management of the multi-junction device and, through the regulation of the SnOₓ/IZO intermediate layer, optimized the internal light-field distribution and the current matching among the sub-cells in the triple-junction device, ultimately achieving a certified steady-state power conversion efficiency of 32.22%. This study demonstrates that precise molecular engineering of organic functional molecules, enabling synergistic regulation of chemical defects and local electric fields at perovskite interfaces at the molecular scale, is an effective approach to reducing voltage losses and improving the performance of multi-junction solar cells.
The first author of the paper is Xu Ye, a postdoctoral researcher jointly cultivated by SEU and Trina Solar. The corresponding authors include Yao Huifeng from the School of Chemistry and Chemical Engineering, SEU; Zhang Hong from Fudan University; and Gao Jifan, Chen Yifeng, Zhang Xueling, and Xie Zhigang from Trina Solar. Among others, SEU is a co-corresponding institution.
Paper’s link: https://www.nature.com/articles/s41586-026-11010-8.
Source: School of Chemistry and Chemical Engineering, SEU
Translated by: Melody Zhang
Edited by: Leah Li
