CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

5.5.2. Eu 3+ doped ZnGa 1.5 In 0.5 O 4 nanoparticles: Emission spectrum of Eu 3+ doped
ZnGa 1.5 In 0.5 O 4 nanoparticles excited at 280 nm is shown in Fig.104 (a). It consists of a broad
band around 460 nm over which sharp peaks ~ 590, 615, 700 nm are superimposed. The
broad band is a characteristic emission of ZnGa 1.5 In 0.5 O 4 host material and sharp peaks
correspond to 5 D 0 → 7 F 1 , 5 D 0 → 7 F 2 and 5 D 0 → 7 F 4 transitions of Eu 3+ ion. Excitation spectra
were monitored at 460 and 615 nm emissions (Fig.104 (b)).
Normalised intensity
1.0
0.8
0.6
0.4
0.2
0.0
(a)
λ exc
= 280 nm
5 7
D0 F1
5 7
D0 F2
5 7
D0 F4
400 500 600 700
Wavelength (nm)
Normalised intensity
1.0
0.8
0.6
0.4
0.2
0.0
Host absorption
Eu-O Charge transfer
λ em
=
615 nm
460 nm
200 250 300 350 400
Wavelength (nm)
(b)
Intensity (arb.units)
1000
100
10
λ exc
=280nm, λ em
=615 nm
0 1 2 3
Time (ms)
(c)
4
Fig.104. (a) Emission spectrum obtained after 280 nm excitation and (b) excitation spectra
obtained after monitoring 615 nm and 460 nm emissions along with (c) the decay
curve corresponding to 5 D 0 level of Eu 3+ in ZnGa 1.5 In 0.5 O 4 nanoparticles.
The excitation spectrum monitored at 460 nm emission showed only one peak at 280
nm corresponding to host absorption of the material. Unlike this excitation spectrum
monitored at 615 nm emission consists of sharp peaks above 300 nm along with broad
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