Self-assembled hole-selective contact for efficient Sn-Pb perovskite solar cells and all-perovskite tandems

Zhu, J., Huang, X., Luo, Y. et al. Nat Commun, 240 (2025). https://doi.org/10.1038/s41467-024-55492-4

Researchers from institutions in China, including Sichuan University, Fujian Normal University, and Xiamen University, have developed new self-assembled monolayers (SAMs) for more efficient perovskite solar cells. The SAMs, named MBT, EBT, and MEBT, are based on a donor-acceptor molecule with different length oligoether side chains. These SAMs act as hole-selective contacts (HSCs), improving charge extraction and reducing defects in Sn-Pb perovskite films. Specifically, EBT led to a 23.54% efficiency in single-junction cells and 28.61% in all-perovskite tandem solar cells. The improved performance is attributed to the enhanced perovskite film quality, reduced non-radiative losses and superior hole extraction

PAIOS system was used to perform Mott-Schottky plots and electrochemical impedance spectroscopy (EIS) measurements. These measurements are used to characterize the electrical properties of the solar cells.

• Mott-Schottky plots are used to determine the built-in potential of the solar cell, which is related to the driving force for charge separation.

• EIS measurements can reveal information about charge transport and recombination processes within the device. In the context of the study, the EIS results corroborate the suppressed non-radiative recombination losses, that were also shown in other tests.