Systhesis, phase transformation and photoluminescence properties of Eu:La1xGdxVO4 nanofibers by electrospinning method
One dimensional Eu:La 1 x Gd x VO 4 nanofibers were successfully prepared via an electrospinning method. Thermogravimetry and differential scanning calorimeter (TG-DSC), X-ray diffraction, Raman spectroscopy, scanning electron microscopy and photoluminescence were used to characterize the samples. T...
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Zusammenfassung: | One dimensional Eu:La
1
x
Gd
x
VO
4
nanofibers were successfully prepared
via
an electrospinning method. Thermogravimetry and differential scanning calorimeter (TG-DSC), X-ray diffraction, Raman spectroscopy, scanning electron microscopy and photoluminescence were used to characterize the samples. The nanofibers crystallized well below 600 °C and with the increase of Gd contents, the nanofibers crystallized in a zircon-type structure. The Raman spectra shifted to higher frequency with the increase of Gd content for zircon Eu:La
1
x
Gd
x
VO
4
. The peaks of photoluminescence spectra shift towards longer wavelength when Gd replaces La and when
x
= 0.4, the photoluminescence intensity reaches its maximum value. The band structure and density of states of
m
-LaVO
4
,
t
-LaVO
4
,
t
-LaGdVO
4
and
t
-GdVO
4
were calculated by local-spin density approximation (LSDA) band theory with Hubbard term of
U
. The band gap of
t
-LaGdVO
4
is just the average of
t
-LaVO
4
and
t
-GdVO
4
. In
t
-LaGdVO
4
, La 5p states are highly localized.
m
-LaVO
4
doped with GdVO
4
changes into
t
-LaVO
4
and a maximum photoluminescence intensity is observed for Eu:La
0.6
Gd
0.4
VO
4
nanofibers. |
---|---|
ISSN: | 2040-3364 2040-3372 |
DOI: | 10.1039/c2nr31135f |