July 1, 2025 – The research group of Haibing Xie, in collaboration with teams led by Xiong Li (Huazhong University of Science and Technology/Hainan University) and Bin Hu (Huazhong University of Science and Technology), has published a research paper in Nature Communications titled " Cross-linked multifunctional bilayer polymer buffer for enhanced efficiency and stability in perovskite solar cells." Assistant Professor Haibing Xie is a co-corresponding author, and Institute for Advanced Study of Shenzhen University is a co-corresponding institution.

The study addresses the stability challenges arising from chemical interactions between metal electrodes and perovskite components by designing a bilayer multifunctional polymer buffer layer composed of polyethyleneimine (PEI) and 2-((2-methyl-3-(2-((2-methylbutanoyl)oxy)ethoxy)-3-oxopropyl)thio)-3-(methylthio)succinic acid (PDMEA), inserted at the interface between the metal electrode and the transport layer (Fig. 1). This buffer layer mitigates metal atom diffusion through the formation of thioether-metal-carboxylate chelation rings between the metal layer and PDMEA. Additionally, it facilitates efficient electron transport and suppresses interfacial recombination via in situ crosslinking between the carboxyl groups of PDMEA and the amine groups of PEI, based on Lewis acid-base reactions. Consequently, this design effectively reduces detrimental metal/ion interdiffusion during device fabrication and operation. Perovskite solar cells incorporating the PEI/PDMEA buffer layer achieved certified power conversion efficiencies of 26.46% (0.1 cm²) and 24.70% (1.01 cm²), along with improved thermal and operational stability. This bilayer polymer buffer strategy, formed by crosslinking polymers with distinct functionalities, provides a novel approach for the rational design of buffer layers in highly efficient and stable perovskite solar cells and other related electronic devices.

This research was supported by the Shenzhen Pengcheng Peacock Program Startup Fund and the Shenzhen University High-Level University Construction Phase II Startup Fund (No. 000002112129).

Original article link: https://www.nature.com/articles/s41467-025-61294-z

Fig. 1 Innovative Bilayer Polymer Buffer Layer (PEI/PDMEA) Boosts Efficiency and Stability of Perovskite Solar Cells