Fig. 5: Stability of the resultant CDs@SiO2 against strong oxidants, strong acids and bases, water, and polar solvents.

a, d Phosphorescence spectra and time-resolved phosphorescence decay of the untreated CDs@SiO2-600 and CDs@SiO2-600 oxidized by H2O2 (30 wt%), concentrated HNO3 (30 wt%), or H2SO4 (98 wt%). b, e Phosphorescence spectra and time-resolved phosphorescence decay of the CDs@SiO2-600 in solvents with different polarities. c, f Phosphorescence spectra and time-resolved phosphorescence decay of the CDs@SiO2-600 under pH values from 1.0 to 14.0. g Phosphorescent lifetime histogram of CDs@SiO2-600 in various oxidants, polar solvents, and pH values from 1.0 to 14.0. h Corresponding photographs of CDs@SiO2-600 in various oxidants, polar solvents, and water at different pH under sunlight, UV on and off.