Post-Ammonia-Treated V<sub>2</sub>CT<i><sub>x</sub></i> MXene at Different Pressures: Effects on Morphology, Electronic, and Optical Properties
Monidipa Pramanik, Mukta V. Limaye, Mahendra S. Pawar, Dattatray J. Late, Shashi B. Singh
Abstract
In the present work, vanadium carbide (V 2 CT x ) MXene was synthesized successfully and then treated with an ammonia solution (NH 4 OH) under different pressures using a hydrothermal process. The sample morphology reveals that the V 2 CT x MXene gradually changed from uneven multilayered micrometre-size sheets to uniform few-layered nanometer-size sheets as the pressure increased. The optical emission spectra show broad emission and a blue shift due to nitrogen-related defects and quantum confinement. X-ray photoelectron spectroscopy shows the presence of nitrogen in all of the samples. The ultraviolet photoelectron spectroscopy study shows a modified density of states near the Fermi level and a maximum of ∼0.6 eV valence band edge shift towards a higher binding energy side after post-treatment with ammonia. More interestingly, the E 1g Raman band becomes degenerate and the E 1g band upshifts (∼15 cm –1 ) with increasing pressure treatment. The Raman results suggest that the induced lattice strain due to post-ammonia treatment plays a crucial role in deciding the optical and electronic properties.