XRD measurements
were taken with a Stoe X-ray diffractometer using Cu Kα1 radiation (λ = 1.5406 Å). SEM images of samples
were performed on a FEI-Q FEG250 microscope, equipped with an EDAX
system. XPS data were recorded on an ESCALAB 250 spectrometer with
a monochromatized Al Kα1 X-rays as the excitation
source. All binding energies were corrected by fitting the C 1s peak
of surface adventitious carbon at 284.8 eV. The optical absorption
of the samples was studied using a Lambda-950 UV–vis spectrometer.
The steady-state PL spectra were recorded on an Edinburgh FLS980,
under an excitation wavelength of 380 nm. Nitrogen adsorption–desorption
isotherms at 77 K were carried out on a Micromeritics 3Flex surface
analyzer. Before the measurement, all the samples were degassed at
130 °C for 12 h under flowing N2. TEM images were
obtained on a CM200FEG PHILIPS operated at 200 kV, equipped with an
EDAX system and a GATAN Tridiem Image Filter. TGA was performed from
room temperature to 800 °C at a heating rate of 10 °C min–1 under O2. Fluorescence lifetime data were
acquired on a home-built confocal FLIM microscope based on a single
photon counting (TCSPC) device (Picoquant). The pulse frequency of
the 485 nm laser diode was set at 5 MHz, and the emission was filtered
by a 530 ± 25 nm bandpass filter.
were taken with a Stoe X-ray diffractometer using Cu Kα1 radiation (λ = 1.5406 Å). SEM images of samples
were performed on a FEI-Q FEG250 microscope, equipped with an EDAX
system. XPS data were recorded on an ESCALAB 250 spectrometer with
a monochromatized Al Kα1 X-rays as the excitation
source. All binding energies were corrected by fitting the C 1s peak
of surface adventitious carbon at 284.8 eV. The optical absorption
of the samples was studied using a Lambda-950 UV–vis spectrometer.
The steady-state PL spectra were recorded on an Edinburgh FLS980,
under an excitation wavelength of 380 nm. Nitrogen adsorption–desorption
isotherms at 77 K were carried out on a Micromeritics 3Flex surface
analyzer. Before the measurement, all the samples were degassed at
130 °C for 12 h under flowing N2. TEM images were
obtained on a CM200FEG PHILIPS operated at 200 kV, equipped with an
EDAX system and a GATAN Tridiem Image Filter. TGA was performed from
room temperature to 800 °C at a heating rate of 10 °C min–1 under O2. Fluorescence lifetime data were
acquired on a home-built confocal FLIM microscope based on a single
photon counting (TCSPC) device (Picoquant). The pulse frequency of
the 485 nm laser diode was set at 5 MHz, and the emission was filtered
by a 530 ± 25 nm bandpass filter.