Fig. 1. (A) XRD patterns of precursors, YR, YR-Si, and YR-Si-Cu2S; (B) FTIR spectra of each step of the synthesized samples of precursor, YR, YR-Si, YR-Si-NH2, and YR-Si-Cu2S; (C) Zeta potential of YR-Si, YR-Si-NH2, and Cu2S; (D) XPS profile of Cu 2p of Cu2S films.

Fig. 2. (A) Schematic diagram of YR-Si-Cu2S; TEM images of (B) YR, (C) YR-Si, and (D) YR-Si-Cu2S; (E) single particle of YR-Si-Cu2S and high magnification of different zones of f and g are shown in (F) and (G), respectively. (H) HAADF-STEM image and cross-section compositional line profiles of samples and elemental mapping images in (I).

Fig. 3. (A) NIR emission spectra of YR, YR-Si, and YR-Si-Cu2S under 808 nm; (B) UV-vis-NIR absorption spectra of PBS buffer solution, Cu2S, YR-Si, and YR-Si-Cu2S dispersed in PBS; (C) schematic diagram of the NIR light penetration depth in different thicknesses of pork tissue; (D) measured NIR emission intensity as a function of injection depth in pork under 808 nm; and (E) NIR emission intensity ratio of I980/I900–1150 in YR-Si-Cu2S with different injection depth.

Fig. 4. Power-dependent temperature of (A) YR, YR-Si, YR-Si-Cu2S and (B) Y-Si-Cu2S as a function of time under 808 nm; (C) normalized UC emission spectra of Y-Si at about 537 nm with the increasing temperature to 420 K; (D) absolute/relative sensitivities of Y-Si at different temperatures; and (E) schematic of temperature measurement using FIR and thermal camera. The inset in (E) is surface and sub-tissue temperatures with different 808 nm powers.

Fig. 5. (A) Photos of E. coli and S. aureus ablation; (B) bacteria viability of E. coli and S. aureus colonies with different incubated conditions under 808 nm.