Molecular vibration data were collected
with a Fourier transform infrared (FT-IR) spectrometer (BRUKER Tensor
27). The Raman spectrum was recorded on a Raman spectrometer (Teksan
Takram-532 nm laser excitation). The elemental composition and contents
were measured by X-ray photoelectron spectroscopy (XPS) (SPECS UHV
analysis system). High-resolution transmission electron microscopy
(HR-TEM) was accompanied by the use of an FEI Tecnai G2 F20 SuperTwin TEM (accelerating voltage: 200 kV). Microstructures
and dispersion of S,N-CQDs were observed by field emission scanning
electron microscopy (FE-SEM), (MIRA 3-XMU) equipped with energy-dispersive
X-ray spectroscopy (EDS), (TESCAN MIRA II). X-ray diffraction (XRD)
analysis was performed on an X-ray powder diffractometer (Philips
PW1730). The specific Brunauer–Emmet–Teller (BET) surface
area was evaluated by nitrogen adsorption at 77 K (Bell Belsorb-mini
II). UV–vis absorption and fluorescence spectra were scanned
using a UV–visible spectrophotometer (Jasco V-750) and fluorescence
spectrophotometer (Jasco FP-8300), respectively. The fluorescence
lifetime decay of samples was studied on a steady state and a transient
state fluorescence spectrometer (Edinburgh Instruments ex-demo equipment
f900 spectrophotometer). MILESTONE MICROSYNTH was utilized to synthesize
S,N-CQDs via microwave-assisted synthesis.
with a Fourier transform infrared (FT-IR) spectrometer (BRUKER Tensor
27). The Raman spectrum was recorded on a Raman spectrometer (Teksan
Takram-532 nm laser excitation). The elemental composition and contents
were measured by X-ray photoelectron spectroscopy (XPS) (SPECS UHV
analysis system). High-resolution transmission electron microscopy
(HR-TEM) was accompanied by the use of an FEI Tecnai G2 F20 SuperTwin TEM (accelerating voltage: 200 kV). Microstructures
and dispersion of S,N-CQDs were observed by field emission scanning
electron microscopy (FE-SEM), (MIRA 3-XMU) equipped with energy-dispersive
X-ray spectroscopy (EDS), (TESCAN MIRA II). X-ray diffraction (XRD)
analysis was performed on an X-ray powder diffractometer (Philips
PW1730). The specific Brunauer–Emmet–Teller (BET) surface
area was evaluated by nitrogen adsorption at 77 K (Bell Belsorb-mini
II). UV–vis absorption and fluorescence spectra were scanned
using a UV–visible spectrophotometer (Jasco V-750) and fluorescence
spectrophotometer (Jasco FP-8300), respectively. The fluorescence
lifetime decay of samples was studied on a steady state and a transient
state fluorescence spectrometer (Edinburgh Instruments ex-demo equipment
f900 spectrophotometer). MILESTONE MICROSYNTH was utilized to synthesize
S,N-CQDs via microwave-assisted synthesis.