Fig. 1. Schematic diagram and characterization of crystal structure of MoS₂. (a) Schematic diagrams of 2H-phase MoS₂ crystal structure and monolayer MoS₂ structure; (b) XRD pattern of MoS₂ QDs

Fig. 2. TEM images, HR-TEM images and particle size statistics of MoS₂ QDs. (a) TEM image of MoS₂ QDs-1; (b) HR-TEM image of MoS₂ QDs-1; (c) particle size statistics of MoS₂ QDs-1; (d) TEM image of MoS₂ QDs-2; (e) HR-TEM image of MoS₂ QDs-2; (f) particle size statistics of MoS₂ QDs-2

Fig. 3. AFM images, height analysis images and AFM three-dimensional images of MoS₂ QDs. (a) AFM image of MoS₂ QDs-1; (b) height analysis image of MoS₂ QDs-1; (c) AFM three-dimensional image of MoS₂ QDs-1; (d) AFM image of MoS₂ QDs-2; (e) height analysis image of MoS₂ QDs-2; (f) AFM three-dimensional image of MoS₂ QDs-2

Fig. 4. FT-IR images and XPS spectra of MoS₂ QDs. (a) FT-IR image of MoS₂ QDs; (b) full spectrum of MoS₂ QDs XPS; (c) Mo 3d spectrum of MoS₂ QDs XPS; (d) S 2p spectrum of MoS₂ QDs XPS

Fig. 5. UV-vis absorption spectra and fluorescence excitation and emission spectra of MoS₂ QDs. (a) UV-vis absorption spectrum of MoS₂ QDs-1; (b) UV-vis absorption spectrum of MoS₂ QDs-2; (c) fluorescence excitation and emission spectra of MoS₂ QDs-1; (d) fluorescence excitation and emission spectra of MoS₂ QDs-2

Fig. 6. PL spectra and 1931 CIE images of MoS₂ QDs. (a) Three-dimensional PL spectra of MoS₂ QDs-1 at different excitation wavelengths; (b) three-dimensional PL spectra of MoS₂ QDs-2 at different excitation wavelengths; (c) 1931 CIE image of MoS₂ QDs-1 under excitation wavelengths of 270-360 nm; (d) 1931 CIE image of MoS₂ QDs-2 under excitation wavelengths of 270-360 nm