Figure 1.

Structural and optical characterization of Ti₃C₂T_x. (A) Representative atomic force microscopy (AFM) image of a single-layer Ti₃C₂T_x flake dispersed on a Si/300 nm SiO₂ substrate with an average thickness of 1.16 ± 0.11 nm. Inset: Thickness profile from point 1 to point 2. Scale bar is 1 μm. (B) Representative Raman spectrum of dispersed Ti₃C₂T_x flakes. Red arrows indicate the internal vibration modes of Ti₃C₂T_x, and the gray region indicates vibration modes of surface terminations, T_x. (C) Average vis–NIR absorption spectra of Ti₃C₂T_x suspensions of different concentrations (bottom to top: 10, 20, 30, 40, and 50 μg/mL) (n = 3). Inset: Optical image of Ti₃C₂T_x suspensions of different concentrations. Scale bar is 2 cm. (D) Absorbance as a function of Ti₃C₂T_x suspension concentration at 635 nm (red) and 808 nm (black), respectively. Data are presented as mean ± SD (n = 3).