Investigation of charge carrier dynamics in a Ti3C2Tx MXene for ultrafast photonics applications

Abstract

The rapid advancement of nanomaterials has paved the way for various technological breakthroughs, and MXenes, in particular, have gained substantial attention due to their unique properties such as high conductivity, broad-spectrum absorption strength, and tunable band gaps. This article presents the impact of the process parameters on the structural and optical properties of a Ti₃C₂T_x MXene for application in ultrafast dynamics. The synthesis of a singular-phase MXene derived from the MAX phase Ti₃AlC₂ was validated through X-ray diffraction (XRD) and Raman spectroscopy analyses. The complete etching of Al and increase in the interplanar distance are also observed upon centrifugation at a very high speed. The influence of varying centrifugation speeds, expressed in rotations per minute (rpm), has been employed to understand the ultrafast spectrum and charge carrier dynamics of the MXene. The investigation revealed the carrier lifetime is critically influenced by rotations per minute (rpm), e.g. showed by a notably swifter decay lifetime at 10 000 rpm compared to 7000 rpm. The electronic relaxation probed using the time-resolved photoluminescence (TRPL) technique exhibits average decay times (τ_av) of 5.3 ns and 5.13 ns at 7k and 10k rpm, respectively, which confirms that the optical properties of the MXene are strongly affected by the centrifugation speed. The synthesized MXene at 10k rpm typically suggests that radiative processes are due to a longer decay lifetime and it experiences fewer non-radiative losses, resulting in its enhanced luminescence properties.