Engineering the decay time of Ti3C2Tx MXene by gold nanoparticle decoration

Abstract MXenes, specifically Ti3C2Tx having peculiar structural and electronic characteristics display not only high surface area, 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 Au NP-decorated multilayer Ti3C2Tx MXene (Au-Ti3C2Tx) synthesized by a simple two-step selective etching technique. Incorporation of Au NPs in the multilayer Ti3C2Tx MXene leads to lattice expansion, reduction in the micro-strain, and improvement in the crystallinity, as confirmed by XRD analysis. Observation of a well-developed G band in the Au-Ti3C2Tx 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-Ti3C2Tx MXene also exhibits promising optical properties for different concentrations of gold. The time-resolved photoluminescence spectroscopy studies displayed a reduction in the average decay time (τav) to ~ 30 % with increasing gold concentration from 100 μL to 150 μL in Au NPs solution which is explained on the basis of Au NPs induced surface plasmon resonance. Au NPs decoration is also assisted in the accumulation of carbon on the MXene surface which leads to improvement in the crystallinity and reduction micro-strain as well as decay time. Thus, engineering decay time through noble metal NPs decoration onto the MXene enables the fabrication of highly efficient photodetectors and imaging devices, particularly beneficial in applications where shorter decay times are preferred.