Researchers at the Stavropoulos Center have uncovered the origin of a long-debated electronic anomaly in one of the most widely studied MXenes, Ti3C2Tx. Our new paper, published in Advanced Functional Materials, shows that the unusual behavior near room temperature is caused not by the MXene alone, but by tiny titanium suboxide domains — primarily Ti3O5 — that form naturally within the layered material.
MXenes are promising two-dimensional materials for electronics, sensing, energy storage, and electromagnetic shielding. Yet Ti3C2Tx has repeatedly shown puzzling changes in its electrical and magnetic properties around room temperature, 350-380 K, where most electronics operate. Using a broad set of in situ techniques — including Raman spectroscopy, X-ray diffraction, calorimetry, conductivity measurements, electron paramagnetic resonance, and magnetometry — the team found that these anomalies coincide with phase transitions of confined titanium suboxides.
The discovery reframes Ti3C2Tx as a subtle MXene–oxide composite, where even a small fraction of oxide nanodomains can strongly affect electronic behavior. Rather than viewing oxidation only as degradation, the work suggests it could become a tool for engineering new functionality.
By controlling these hidden suboxide phases, researchers may be able to design MXene-based devices with near-room-temperature phase-change behavior, including thermal latching, opto-thermal switching, and robust electronic response under real-world conditions.