Tailoring Electronic and Optical Properties of MXenes through Forming Solid Solutions

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Chemistry

Background:

• Alloying is a established method for tuning metal properties.
• Two-dimensional transition metal carbides (MXenes) offer compositional flexibility at M and X sites for property modification.

Purpose of the Study:

• To investigate the impact of M-site elemental substitution on MXene properties.
• To explore the creation of solid-solution MXenes for tailored electronic and optical characteristics.

Main Methods:

• Systematic investigation of three binary solid-solution MXene systems: Ti2-yNbyCT, Ti2-yVyCT, and V2-yNbyCT.
• Analysis of electronic and optical property evolution as a function of composition.
• Characterization of metal sublattice solubility and element distribution.

Main Results:

• All investigated MXene systems exhibit unlimited solubility and random metal element distribution.
• Optical properties are tunable non-linearly, with absorption peaks spanning UV to near-infrared wavelengths.
• Macroscopic electrical conductivity is controllable over 3 orders of magnitude at room temperature and 6 orders at 10–300 K.

Conclusions:

• M-site solid solutions significantly expand the range of nonstoichiometric MXenes.
• This work provides a pathway for precisely controlling the physical properties of MXenes through compositional engineering.
• The findings open avenues for developing MXenes with a vast array of compositions and functionalities.