Research Paper: Enlarging moment and regulating orientation of buried interfacial dipole for efficient inverted perovskite solar cells

Summary

This study introduces an interfacial dipolar chemical bridge strategy using 2-(Diphenylphosphino) acetic acid (2DPAA) to address critical carrier transport and recombination issues at the buried interface of inverted perovskite solar cells (PSCs). The main goal was to enlarge the interfacial dipole moment and regulate its orientation to enhance performance and stability. Key findings show that 2DPAA effectively enlarges the interfacial dipole moment to 5.10 D and optimises it to a positive dipole orientation, accelerating vertical hole transport, suppressing nonradiative recombination, and promoting perovskite crystallization. This resulted in champion inverted devices achieving a remarkable power conversion efficiency (PCE) of 26.53% (certified 26.02%). The strategy also yielded high PCEs for wide-bandgap (22.02%) and large-area (24.11%) devices. Furthermore, unencapsulated devices demonstrated excellent long-term stability, retaining over 95.4% of initial efficiency after 1200 hours of inert storage and 94.3% after 1200 hours of light soaking.

Why it matters

These findings are crucial for advancing inverted PSC technology by providing a comprehensive solution to fundamental limitations in carrier transport and recombination, which often restrict further development. By offering a strategy to simultaneously achieve record efficiencies and exceptional stability, this research provides significant guidance for creating more robust and commercially viable next-generation solar cells. The universality of this approach across different perovskite types (narrow-bandgap, wide-bandgap, and large-area devices) also highlights its broad applicability for high-performance photovoltaics.

How Fluxim tools used

The Paios platform from Fluxim was instrumental in the electrical characterisation of the PSCs. Specifically, Paios was used for Mott-Schottky (M-S) plots to extract the built-in potential (Vbi), which was found to be larger for 2DPAA-treated devices (1.14 V vs 1.10 V). Transient photocurrent (TPC) measurements were performed to quantify the average charge transit time (τave), revealing a significant decrease from 4.93 μs for control to 2.89 μs for 2DPAA-treated devices, indicating more efficient hole transport. Additionally, electrochemical impedance spectroscopy (EIS) was conducted using Paios, confirming a lower series resistance and higher recombination resistance in the 2DPAA-treated devices, consistent with faster carrier transport and suppressed recombination.

Publication Details

Peng, Y., Chen, Y., Zhou, J., Luo, C., Tang, W., Duan, Y., Wu, Y. and Peng, Q. (2025), Enlarging moment and regulating orientation of buried interfacial dipole for efficient inverted perovskite solar cells. Nature Communications. https://doi.org/10.1038/s41467-024-55653-5