Thermal escalab 250xi

X-ray diffraction (D8 Advance X-ray diffractometer, Bruker AXS, Germany) was used to measure the phase composition of the CPDs powder by a Cu Kα radiation at a voltage of 40 kV and current of 40mA under a scan speed of 0.1sec/step at room temperature. The diffraction angle 2θ ranges from 10° to 70°. X-ray photoelectron spectrometry (XPS) experiments were performed by a Thermal ESCALAB 250XI X-ray source system (Thermo Fisher Scientific, USA). The excitation and emission spectra of the CPDs aqueous solutions were recorded on a spectrofluorometer (FS5, Edinburgh Instruments, England) at room temperature. The absolute quantum yield (QY) of this CPDs was measured by the spectrofluorometer (FS5, Edinburgh Instruments, England) at room temperature. The UV-vis absorption spectra of CPDs aqueous solutions were recorded by an UV-mini1240 spectrophotometer (Shimadzu, Japan). Fourier transform infrared (FT-IR) spectroscopy was conducted on a Bruker IFS 66/S spectrophotometer. The pure CPDs powder was mixed with KBr and then compressed into a crucible for FTIR scanning. The spectra were recorded over the range 4000–500cm⁻¹ with a resolution of 4 cm⁻¹. Morphology of the samples were analyzed by a high-resolution transmission electron microscopy (TEM) on Hitachi 9500 TEM and Hitachi HD-2000 STEM systems.