Two-Dimensional CrCl₃ Nanosheets via Liquid-Phase Exfoliation in Aqueous Medium for Spintronic Applications

Chromium trihalides, like CrCl 3, are part of an emerging class of van der Waals materials that have been showing promise for their magnetic properties. However, CrCl 3 has been produced only by mechanical tape exfoliation, a low yield method, and by liquid exfoliation in organic solvents, with a negative impact on the environment and human health. Here, CrCl 3 was produced for the first time by liquid-phase exfoliation (LPE) in aqueous medium, in the presence of polyvinylpyrrolidone (PVP10) or sodium dodecyl sulfate (SDS), followed by ultrasonication. It was also the first time that CrCl 3 was obtained with nanometric size (<100 nm), and its photothermal, magnetic, and water stability performances were studied. Results showed that CrCl 3 + SDS (zeta potential = −19.9 mV) had better water stability than CrCl 3 + PVP10 (zeta potential = 8.6 mV). CrCl 3 + SDS and CrCl 3 + PVP10 were obtained with a mean particle lateral size of 39.4 ± 15.9 and 65.6 ± 47.4 nm and a mean thickness of 4.4 ± 3.9 and 7.1 ± 5.3 nm, respectively. Both materials revealed a similar ability to convert near-infrared light into heat, showing a temperature increase of 4.7 °C (CrCl 3 + SDS) and 5.8 °C (CrCl 3 + PVP10) after 30 min of irradiation. Results show that the presence of SDS during production leads to a loss of Cl atoms when compared to PVP10, but crystallinity is preserved. Magnetometry measurements show a Néel temperature of 15 K ± 2.0 K for both samples, showing its antiferromagnetism. A Curie–Weiss analysis indicates a ferromagnetic dominant paramagnetic phase due to the positive Curie–Weiss temperatures, with the calculated effective moments as 4.20 μ B ± 0.63 μ B and 3.95 μ B ± 0.49 μ B for CrCl 3 + PVP10 and CrCl 3 + SDS, respectively. These results show that LPE of CrCl 3 with PVP10 or SDS produces 2D CrCl 3, preserving crystallinity and magnetic properties, and demonstrating potential for spintronic applications.