Hot Electrons in 2D Coordination Polymers: Record-Breaking Charge Mobility Challenges Organic Material Limits

Summary: A groundbreaking study reveals highly mobile hot carriers in 2D conjugated coordination polymers (2D c-CPs), challenging the paradigm that organic materials are unsuitable for non-equilibrium charge transport applications.

In a paper published in Nature Materials, researchers from the Technische Universität Dresden, the Max Planck Institute for Polymer Research, the Max Planck Institute of Microstructure Physics, and collaborating institutions demonstrated that Cu₃BHT films exhibit record-breaking hot carrier mobility (~2,000 cm² V⁻¹ s⁻¹) and quasi-equilibrium band-like transport (~400 cm² V⁻¹ s⁻¹), unlocking new possibilities for organic-based optoelectronics.

Using ultrafast spectroscopy and microscopy, the team tracked hot carriers traversing ~300 nm grain boundaries within picoseconds, far surpassing conventional organic materials. The material’s low thermal conductivity and unique phonon dynamics enable a hot-phonon bottleneck, prolonging carrier lifetimes to ~750 fs, comparable to state-of-the-art perovskites. This combination of electrical conductivity and thermal insulation mirrors the “electron-crystal phonon-glass” ideal for thermoelectrics and hot-carrier devices.

The work, published in Nature Materials, highlights Cu₃BHT’s potential in hot-electron transistors, photovoltaics, and photocatalysis. Its solution processability and structural tunability position 2D c-CPs as versatile platforms for next-generation organic electronics. Collaborative efforts included advanced characterization techniques such as time-resolved terahertz spectroscopy and atomic-resolution microscopy.

Acknowledgements: This work is financially supported by ERC starting grant (FC2DMOF, no. 852909), CRC 1415 (Chemistry of Synthetic Two-Dimensional Materials, no. 417590517), SPP 2244 (2DMP), and RTG 2861 (no. 491865171). The authors acknowledge B. Liang for the AC-HRTEM characterization, J. Zhang for the X-ray absorption near-edge structure and extended X-ray absorption fine structure measurements, and Y. Zou for the XPS and UPS measurements. R.D. thanks the National Natural Science Foundation of China (22272092; 22472085), Natural Science Foundation of Shandong Province (ZR2023JQ005), and Taishan Scholars Program of Shandong Province (tsqn201909047). P.S.P. is grateful to the European Union-NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria, project no. BG-RRP-2.004-0008 for the financial support and Discoverer PetaSC and EuroHPC JU for awarding access to DISCOVERER supercomputer resources. The authors acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at PETRA III and the authors would like to thank C. Shen for assistance in using beamline P08. Beamtime was allocated for proposal I-20230095. M.H. and S.C.B.M would like to thank J. Perez for assistance with the GIWAXS measurements.

Reference: Shuai Fu, Xing Huang, Guoquan Gao, Petko St. Petkov, Wenpei Gao, Jianjun Zhang, Lei Gao, Heng Zhang, Min Liu, Mike Hambsch, Wenjie Zhang, Jiaxu Zhang, Keming Li, Ute Kaiser, Stuart S. P. Parkin, Stefan C. B. Mannsfeld, Tong Zhu, Hai I. Wang, Zhiyong Wang, Renhao Dong, Xinliang Feng, and Mischa Bonn. Unveiling high-mobility hot carriers in a two-dimensional conjugated coordination polymer. Nat. Mater. (2025). https://www.nature.com/articles/s41563-025-02246-2