Recently, a joint research team led by Prof. Zhang Tiankai from the School of Materials Science and Engineering, SEU, together with Professors Li Yaowen and Chen Xiankai from Soochow University, proposed a novel design strategy for the interfacial layer of perovskite photovoltaic cells—a self-assembled monolayer (SAM) with a strong “electronic resonance” structure. The related results were published in the top international journal Nature. This study addresses the issue of poor stability of perovskite solar cells under harsh conditions caused by the intrinsically low anchoring strength of traditional interfacial SAMs, offering a new solution.
Perovskite solar cells are thin, lightweight, and flexible, making them suitable for use as flexible power-generating films in wearable devices, building facades, and energy supply for space and polar regions, positioning them as a core next-generation photovoltaic technology. However, a long-standing challenge has been that the charge-extraction interface, which is only a single molecule thick inside the cell, is prone to detachment, generating numerous defects. This leads to a rapid decline in power conversion efficiency under high-temperature and thermal-cycling conditions, posing the major obstacle to large-scale deployment.
Current research has mostly focused on alleviating aging through methods like increasing molecular binding sites or steric hindrance. Studies and designs specifically targeting the intrinsic anchoring strength of SAMs on substrates have not yet been carried out. This team took a different approach, designing a “donor-acceptor-donor” (D-A-D) electronic resonant molecular structure. This strategy amplifies the electron cloud density of the anchoring group, shortens and reinforces the covalent bond connecting the molecule to the substrate, enabling the interfacial molecules to firmly “stick” to the substrate. Simultaneously, the molecules spread more uniformly, balancing power generation efficiency with long-term stability.
The team designed a SAM structure featuring two triphenylamine electron donors and one cyanophosphonic acid electron acceptor. Compared to simple non-"electronic resonance" SAMs, the anchoring cyanophosphonic acid group in this design exhibits a higher electron cloud density. This effectively enhances the anchoring strength of the SAM to the substrate. Consequently, the devices showed significantly improved stability under various harsh operating conditions, including wide temperature cycling from -40°C to 85°C and 85°C thermal aging with illumination. This advancement paves the way for expanding the application of perovskite solar cells to scenarios like polar and space environments.
In terms of application, the novel “electronic resonance” SAM enabled certified power conversion efficiencies (PCEs) of 27.69% on 0.063 cm² small-area devices and 23.63% on 15.64 cm² module devices. The operational stability of encapsulated devices under various harsh aging conditions also achieved breakthrough improvements. Furthermore, the universality of this SAM design strategy was reliably verified on flexible perovskite solar cell devices.
Reviewers forNature commented that this research clarifies the intrinsic correlation between the electronic configuration of the SAM and interfacial robustness, pioneering a new approach in electronic resonance molecular design. This provides a foundational chemical strategy for photovoltaic devices intended for extreme environments. This achievement is expected to support China’s new energy industrial upgrading and provide technological reserves for achieving the nation’s “dual carbon” goals.
Li Yaowen, Chen Xiankai, and Zhang Tiankai are the co-corresponding authors of the paper, with Wu Xiaoxiao and Kou Wenwen as co-first authors.
Paper link: https://www.nature.com/articles/s41586-026-10919-4
Source: SEU News Netwotk
Translated by: Melody Zhang
Edited by: Leah Li
