Engineering the decay time of Ti₃C₂T<i> _x </i> MXene by gold nanoparticle decoration

MXenes, specifically Ti₃C₂T<i>_x</i>having peculiar structural and electronic characteristics display not only high surface area, and excellent thermal and electrical conductivity but also have the potential for functionalization. The primary focus of this research is to control the decay time of gold nanoparticle (NP) (Au NP) decorated multilayer Ti₃C₂T<i>_x</i>MXene (Au-Ti₃C₂T<i>_x</i>) synthesized by a simple two-step selective etching technique. Incorporation of Au NPs in the multilayer Ti₃C₂T<i>_x</i>MXene leads to lattice expansion, micro-strain reduction, and crystallinity improvement, as confirmed by x-ray diffraction analysis. Observation of a well-developed G band in the Au-Ti₃C₂T<i>_x</i>MXene across different Au concentrations by Raman spectroscopy investigations suggests the accumulation of graphitic carbon on the MXene surface which has greatly improved the charge transfer characteristic of the carbide layer. Furthermore, the Au-Ti₃C₂T<i>_x</i>MXene exhibits promising optical properties for different concentrations of gold. The time-resolved photoluminescence spectroscopy studies displayed a reduction in the average decay time (<i>τ</i>_av) to ∼30% with increasing gold concentration from 100 to 150<i>μ</i>l in Au NPs solution which is explained based on Au NPs induced surface plasmon resonance. The decoration of Au NPs facilitates the accumulation of carbon on the surface of MXene, resulting in enhanced crystallinity, reduced micro-strain, and decreased decay time. By engineering decay time through the decoration of noble metal NPs onto MXene, it becomes possible to fabricate highly efficient photodetectors and imaging devices. This is especially advantageous in applications where shorter decay times are desired.