Hot electrons in 2D coordination polymers: record-breaking charge mobility challenges organic material limits

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 recent paper published by Nature Materials, researchers from the Max Planck Institute of Microstructure Physics, the Max Planck Institute for Polymer Research, the Technische Universität Dresden, 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.

The paper entitled “Unveiling high-mobility hot carriers in a two-dimensional conjugated coordination polymer” by 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 can be found at: https://www.nature.com/articles/s41563-025-02246-2