Publication: Ink-processable stable dispersions and tunable hybrid materials from Ti3C2Tx MXenes

In their latest article, Principal Investigator Dr. Hendrik Schlicke (SchlickeLab, Leibniz-Institut für Polymerforschung Dresden (IPF), partner of the network NanoCarbon) and his colleagues demonstrate how MXenes can benefit from concepts familiar to colloidal chemists: By employing ligand functionalization and molecular cross-linking they created ink-processable stable dispersions and tunable hybrid materials from Ti3C2Tx MXenes, which show promising properties for electronics and sensing applications. The article was just published in Advanced Functional Materials: Molecular Cross-linking of MXenes: Tunable Interfaces and Chemiresistive Sensing.

Link: https://doi.org/10.1002/adfm.202518884 (open access)

Abstract:

MXenes, a family of 2D transition metal compounds, have emerged as promising materials due to their unique electronic properties and tunable surface chemistry. However, the translation of these nanoscale properties into macroscopic devices is constrained by suitable cross-linking strategies that enable both processability and controlled inter-flake charge transport. Herein, this study demonstrates the tunability of interfaces and the inter-layer spacing between Ti3C2Tx MXene flakes through molecular cross-linking with homologous diamines. Oleylamine is first used to stabilize MXenes in chloroform, followed by diamine-mediated cross-linking to tune precisely the interlayer spacing. Grazing incidence X-ray scattering (GIXRD/GIWAXS) confirmed the correlation between ligand chain length and inter-layer spacing, which is further supported by Density Functional Theory (DFT) calculations. Furthermore, the charge transport properties of thin films consisting of diamine-cross-linked Ti3C2Tx MXenes are investigated and a strong dependence of the conductivity on the cross-linker length is observed. The dominating charge transport mechanism is variable range hopping (VRH) in accordance with the structure of the films. Finally, chemiresistive vapor sensing is probed using the MXene composites, and a pronounced sensitivity and selectivity for water is observed, highlighting their potential for use in humidity sensors. Insights into molecular cross-linking and its impact on charge transport open avenues for next-generation MXene-based electronic devices.

Authors: Yudhajit Bhattacharjee, Lukas Mielke, Mahmoud Al-Hussein, Shivam Singh, Karen Schaefer, Borja Rodríguez-Barea, Qiong Li, Anik Kumar Ghosh, Artur Erbe, Carmen Herrmann, Yana Vaynzof, Andreas Fery, Hendrik Schlicke