ABSTRACT Quantum Dots (QDs) can be synthesised by chemical method under normal atmosphere. Chemical methods are found to be more economical of all methods, which led to the interest to synthesis QDs through chemical route. The present work focuses the preparation of cadmium Telluride (CdTe) QDs and the formations of CdTe QDs-PVA (poly vinyl alcohol) nanofiber by electrospinning method. The absorption and emission spectra of UV-Visible and Photoluminescence (PL) characterisation confirms the presence of CdTe QDs. The surface morphology and uniformity of CdTe QDs and PVA matrix nanofiber was confirmed through SEM images

P Umarani

P Venkatesan

T Radhakrishnan

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Vol. 8 | No.4 |517 - 521 | October - December | 2015 
ISSN: 0974-1496 | e-ISSN: 0976-0083 | CODEN: RJCABP 
http://www.rasayanjournal.com 
http://www.rasayanjournal.co.in 
 
POLYMER ELECTROSPUN NANOFIBERS                                                                                                                               P. Venkatesan et. al 
DEVELOPMENT AND STUDY OF GSH CAPPED CdTe 
QUANTUM DOTS EMBEDDED POLYMER ELECTROSPUN 
NANOFIBERS 
 
P. Venkatesan*, P.Umarani and T.Radhakrishnan 
Department of Physics, SRC-SASTRA University,  
Kumbakonam-612 001 (Tamil Nadu) India 
*E-mail: venkat.mph86@gmail.com 
 
ABSTRACT 
Quantum Dots (QDs) can be synthesised by chemical method under normal atmosphere. Chemical methods are 
found to be more economical of all methods, which led to the interest to synthesis QDs through chemical route. The 
present work focuses the preparation of cadmium Telluride (CdTe) QDs and the formations of CdTe QDs-PVA 
(poly vinyl alcohol) nanofiber by electrospinning method. The absorption and emission spectra of UV-Visible and 
Photoluminescence (PL) characterisation confirms the presence of CdTe QDs. The surface morphology and 
uniformity of CdTe QDs and PVA matrix nanofiber was confirmed through SEM images. 
Keywords: Nanofibers, Electrospinning, quantum dots, UV-Visible Spectrum, Photoluminescence, Scanning 
Electron Microscope.  
©2015 RASĀYAN. All rights reserved  
 
INTRODUCTION 
Colloidal Semiconductor nanocrystals exhibit unique properties due to quantum confinement effects. 
Quantum Dots (QDs) have good absorption spectra based on the grain size.1-4 QDs can be effectively used 
in optoelectronic devices, optical transformers, photonic switch devices and other applications.5-10 
Cadmium Telluride (CdTe) quantum dots are most extensively studying QDs structure which exhibit size 
tunable optical properties. Photoluminescence properties of the QDs depend on a varying parameters that 
do not affect the absorption properties.11The direct band gap of 1.53 eV makes CdTe useful for a wide 
array of applications.12 Nanofibers are an interesting nanostructure used for several electronics and 
Biomedical applications.13, 14 The nanofiber properties depends on the applied field, the viscosity of the 
polymeric solution, nozzle and collector distance.  Electrospinning process is a more reliable method to 
develop Polymeric nanofibers. This process produces well aligned nanofiber structures, compared to other 
techniques.   
In the present paper, we report on excellent photoluminescence properties of CdTe QDs capped with 
Glutathione (GSH) at various scan rates, which’s structural and absorption properties of prepared CdTe 
QDs and PVA (Poly vinyl alcohol) -CdTe polymeric nanofibers were characterized.               
 
EXPERIMENTAL 
Materials and Methods  
All the chemicals and reagents of synthesized CdTe QDs were obtained from commercial suppliers and 
were used without further purification., Glutathione (GSH), cadmium chloride (CdCl2), Trisodium citrate 
dehydrate, Potassium tellurate (K2TeO3), Sodium Boro hydride (NaBH4), Millipore water and ethanol. 
 
Preparation of GSH capped CdTe Quantum dots 
The colloidal CdTe QDs were synthesized with the capping agent Glutathione (GSH) by colloidal 
method. Add 0.08M Cadmium chloride in 50ml  of Deionised water under stirring for 30 min. Add 0.2 g 
of  Trisodium citrate dehydrate, 0.1g of Glutathione (GSH), 0.02M, 2ml of K2TeO3 and 0.1g of NaBH4 
 
Vol. 8 | No.4 |517 - 521 | October - December | 2015 
POLYMER ELECTROSPUN NANOFIBERS                                                                                                                               P. Venkatesan et. al 
 
518 
successively while stirring, with 30 minutes interval of time. The mixture was reacted at 95˚ C oil bath for 
72 hours. The obtained QDs were precipitated with ethanol and centrifuged till the pH (7.4) of colloidal 
solutions.  
 
Preparation of electrospinning solution 
PVA of 0.15g was dispersed in 15 ml of cool water for 2 h, Heat the mixture for 30 min at 95˚ C in order 
to dissolve the PVA completely. Add 2 g of CdTe colloidal solution under vigorous stirring for 1h. The 
obtained homogenous polymeric blended solution was used for electrospinning.    
 
Preparation of PVA-CdTe polymeric Nanofiber 
As prepared polymeric solution is initially ejected from the tip of a fine nozzle maintained at a potential 
of 20KV by a DC power supply. The fiber is developed by fixing the nozzle and the collector distance to 
about (10-15 cm) with various flow rates.  The diameter range of the nanofibers depends on flow rate, 
nozzle collector distance.  
 
Characteristization Techniques  
The as-prepared semiconductor Quantum dots were characterized by, UV-Visible spectrometer (UV-Vis), 
Scanning Electron Microscopy (SEM), Photoluminence (PL).  
 
RESULTS AND DISCUSSIONS 
UV-Absorption Spectrum 
The as-prepared CdTe Nanoparticles were dispersed in distilled water for UV-absorption analysis. In this 
analysis water was used for baseline Calibration. The prepared sample was taken in Quartz cuvett and the 
absorption spectrum was recorded in the range of 200-1200nm as shown in figures- 1 and 2. From the 
Figure-1, the Maximum absorption range of GSH Capped CdTe nanoparticle was observed from 340nm-
590nm respectively. Figure-2 shows UV-Visible absorption spectra of GSH Capped CdTe nanoparticles 
at various time intervals. By increasing the reflux time, the absorption range increases due to the 
nucleation of CdTe nanoparticles. Using the energy wave equation, the band gap value of nanoparticles 
was 3.68eV. 
200 400 600 800 1000 1200
0.0
0 .5
1 .0
1 .5
2 .0
2 .5
3 .0
3 .5
a
b
s
o
rp
ti
o
n
 i
n
 a
b
s
 u
n
it
w ave leng th  in  nm
 
Fig.-1: UV-Absorption spectrum of GSH-CdTe QDs 
 
Vol. 8 | No.4 |517 - 521 | October - December | 2015 
POLYMER ELECTROSPUN NANOFIBERS                                                                                                                               P. Venkatesan et. al 
 
519 
 
Fig.-2: UV-Absorption spectrum of GSH-CdTe QDs with different refluxing time 
 
Photoluminescence  
The Photoluminescence emission of as prepared nanoparticles on the influence of H2O2 was studied with 
different scan rate as shown in figures-3 and 4. The maximum Photoluminescence intensity was observed 
around 548nm.The Photoluminescence intensity of CdTe capped with GSH nanoparticles decreased with 
various scan rates due to the quenching effect of H2O2. 
 
Fig.-3: Photoluminescence Spectrum of GSH-CdTe QDs 
 
Vol. 8 | No.4 |517 - 521 | October - December | 2015 
POLYMER ELECTROSPUN NANOFIBERS                                                                                                                               P. Venkatesan et. al 
 
520 
3 5 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0 6 5 0 7 0 0 7 5 0
- 1 0 0 0 0 0 0
0
1 0 0 0 0 0 0
2 0 0 0 0 0 0
3 0 0 0 0 0 0
4 0 0 0 0 0 0
5 0 0 0 0 0 0
6 0 0 0 0 0 0
7 0 0 0 0 0 0
8 0 0 0 0 0 0
in
d
e
n
s
it
y
w a v e le n g th
 
Fig.-4: Photoluminesence spectrum of GSH-CdTe QDs with different Scan rate. 
 
SEM Analysis 
Figure-5 shows the surface morphology of GSH capped CdTe nanparticles. It is observed that the 
particles are amorphous in nature with different shapes and sizes. The morphology of GSH capped CdTe 
–PVA nanofibers were characterized by SEM. In this figure-6, due to the high concentration of CdTe 
nanoparticles, the structure of nanofibers was not homogenous.  
 
 
Fig.-5: SEM image of GSH-CdTe QDs 
 
Fig.-6: SEM image of PVA-CdTe QDs composite 
nanofibers. 
 
CONCLUSION 
In this study, a simple and rapid colloidal method was adapted for the preparation of GSH capped CdTe 
QDs. Using the optical absorption studies, the energy gap values were calculated. The Photoluminescence 
studies were studied with different scan rate intensity. Electrospinning method was used to incorporate 
CdTe QDs in PVA nanofibers. In this process the solvents evaporated at a faster rate due to high 
concentration of CdTe, Thus the nanoparticles structure of nanofibers was not founded to be homogenous.  
 
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Vol. 8 | No.4 |517 - 521 | October - December | 2015 
POLYMER ELECTROSPUN NANOFIBERS                                                                                                                               P. Venkatesan et. al 
 
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[RJC-1363/2015]  
 
 


DEVELOPMENT AND STUDY OF GSH CAPPED CdTe QUANTUM DOTS EMBEDDED POLYMER ELECTROSPUN NANOFIBERS

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DEVELOPMENT AND STUDY OF GSH CAPPED CdTe QUANTUM DOTS EMBEDDED POLYMER ELECTROSPUN NANOFIBERS

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