XU Yang-zi, HU He. Preparation and Photoluminescence Properties of ZnS Nanocrystals Co-doped with Mn<sup>2+</sup> and Pb<sup>2+</sup>[J]. Chinese Journal of Luminescence, 2007,28(4): 589-593
XU Yang-zi, HU He. Preparation and Photoluminescence Properties of ZnS Nanocrystals Co-doped with Mn<sup>2+</sup> and Pb<sup>2+</sup>[J]. Chinese Journal of Luminescence, 2007,28(4): 589-593DOI:
Nanocrystals doped with optically active luminescence centers create new opportunities for luminescent study and application of nanoscale materials.ZnS is the most typical and important crystalline phosphor in both applications and basic science
and doping might change its properties
especially
the transition metallic ions co-activated ZnS nanoparticles form a new class of luminescent materials.The arrested chemical precipitation method is the most popular technique that is used in industrial applications because of its cheap raw materials
easy handing and large-scale production
many doped ZnS nano-particles were prepared by this method.In order to volume-produce homodisperse free-standing
with good surface
and high luminescent doped ZnS nanoparticles
polymer PVP was used as surfactant.Preparation produce was as follows:6.0 g PVP was dissolved in 70~80 mL ultrapure water(
R
≈18 MΩ)
while the solution was stirred
10 mL of 1 mol·L
-1
Zn(CH
3
COO)
2
·2H
2
O
and 1~7 mL of 0.1 mol·L
-1
Mn(CH
3
COO)
2
·4H
2
O
0.1~2 mL of 0.1 mol·L
-1
Pb(CH
3
COO)
2
·3H
2
O were then added.After stirring for 15 min
10 mL of 1 mol·L
-1
Na
2
S·9H
2
O was injected
a suspension occurred immediately.After centrifuging and washing the particles twice with distilled water and once with ethanol.The nano-particles were dried in vacuum.All agents used are analytical pure and without further treatment.Nanocrystalline ZnS:Mn
2+
Pb
2+
have been prepared via the precipitation method at room temperature and under ambient conditions.X-ray diffraction analysis shows that the average crystalline particles size of samples is about 2~4 nm.TEM image shows the nanoparticles are homodisperse.By measurement of the fluorescence spectra
the excitation(λ
exc
≈410 nm) and emission(λ
em
≈510~560 nm) wavelength are both in visible-light range.A novel luminescent property has been observed in the photoluminescence(PL) spectra of the ZnS:Mn
2+
Pb
2+
nanocrystals.These nanocrystals can be doped with Mn
2+
and Pb
2+
during the synthesis without altering the X-ray diffraction pattern
however
the PL intensities of the co-doped samples vary with changing of the impurity mole ratios in the Mn
2+
and Pb
2+
co-doped samples
but the emission wavelength is not changed with the changing of the impurity mole ratios.The PL properties of the co-doped samples are dramatically different from those of Mn
2+
and Pb
2+
single doped ZnS nanorystals
and a probable explanation is presented also.All the results strongly reveal that co-doped ZnS nanocrystals form a new class of luminescent materials.