1. BOGALA GRAPHITE AS A CATALYTIC COUNTER ELECTRODE MATERIAL FOR
SnO2/ZnO COMPOSITE DYE- SENSITIEZED SOLAR CELLS
. A.L.Bandara1,2, W.M.S.S.Wanigasekara1,2, G. R. A. Kumara1,2, R. M. G.Rajapakse1,2
1 Postgraduate Institute of Science, University of Peradeniya, Sri Lanka.
2 Department of Chemistry, Faculty of Science, University of Peradeniya, Sri Lanka.
Abstract
In this study properties of Bogala Graphite was investigated as a novel counter electrode(CE) material in composite SnO2/ZnO based
solar cells. Doctor blade technique was used to deposit a film of graphite particles on FTO glass substrate. A SnO2/ZnO composite
thin film of photo anode was fabricated using the spray pyrolysis technique. The optimum thickness of graphite film was found to be
500μm. By the application of graphite CE in composite SnO2/ZnO based solar cell the energy conversion efficiency was significant
showing a value of 2.12% whereas Pt coated CE showed an efficiency of 2.82%.
Introduction
Dye sensitized solar cells(DSSCs) are highlighted in the solar energy research area due to its high efficiency and its production cost
effectiveness. Commonly used Pt coated CE has a high efficiency with along with it’s limitations of hight cost of material value, poor
stability on corrosive electrolytes and high processing temperature. Therefore a novel material Bogala Graphite was investigated
replace Pt as the CE due to Bogala Graphite’s favourable properties such as abundant availability, low cost of material value, good
catalytic activity, hight conductance and high stability to most electrolytes. Modification of CE has been adopted to effectively
decrease the cost of production and to relatively increase the conversation efficiency for the dye sensitized solar cells.
Experimental
SnO2 (15 %) colloidal solution (3 ml), acetic acid (3 drops), ZnO(36 mg)
and Triton X-100 (3 drops)
Ground in a motar
Ethanol (40 ml) was added and ultrasound sonicated for 15 min.
Solution was sprayed on to FTO glass substrates at 150 ºC
Sintered at 500 ºC for 30 min.
Results
Figure 02. I-V characteristics of SnO2/ZnO-based SSCs fabricated in
different film thickness
Figure 04. I-V characteristics of SnO2/ZnO based solar cell with different CE
Figure 05. The XRD pattern for Graphite CE
Conclusion
❖The optimum film thickness for Graphite CE was found to be 500μm .
❖The pattern observed XRD pattern confirms the consistencies of graphite in Majority of CE
❖ The power conversion efficiency form optimised Bogala graphite obtained was 2.12% whereas Pt CE 2.82 % efficient under 1.5AM
illuminance.
References
Preparation of SnO2/ZnO composite films
Ball milled Bogala Graphite (particle size <43 )-(0.75mg)
Ultrasound sonicated for 15 minutes
Stirred at 80 ºC over night
Paste was deposited on FTO glass substrate using Doctor Blade
technique
Sintered at 350 ºC for 30 minutes
Preparation of Graphite CE
Sample I J V FF η %
Graphite CE 1.13 4.54 0.709 0.630 2.12
Pt CE 1.52 5.19 0.727 0.704 2.82
Table 01. Solar cell parameters of SnO2/ZnO-based SSCs fabricated at
with different thicknesses.
Table 02. Solar cell parameters for SnO2/ZnO-based SSC used graphite CE and
Pt CE
Figure 03.SEM images of fabricated graphite CE
Working electrodes were sandwiched with a Pt plated FTO counter
electrode
Intervening space was filled with the liquid electrolyte (0.1 M LiI, 0.05 M I2,
0.6 M dimethylpropylimidazolium iodide, tertiarybutylpiridine in
methoxyacetonitrile)
IV measurements were obtained using solar simulator (PEC-LO1), under
AM 1.5 illumination
Construction of SSCs
Figure 01.fabricate films of (a) SnO2/ZnO composite films
(b)graphite CE (C) assembled DSSC
(a) (c)
(b)
Thickness of CE/µm
J
cm
V FF η %
600 4.36 0.688 66.37 1.99
550 4.93 0.633 62.33 2.00
500 4.74 0.700 63.59 2.12
450 4.89 0.676 61.22 2.03
400 5.19 0.658 59.01 2.01
PhotoCurrent/mAcm-2
0
0.0004
0.0007
0.0011
0.0014
Voltage/V
0.00E+00 1.75E-01 3.50E-01 5.25E-01 7.00E-01
I(500μm)
i(550μm)
i(400μm)
i(450μm)
i(600μm)
Photocurrentdensity/
mAcm-2
0.0
1.4
2.7
4.1
5.4
Voltage/ V
0 0.8
Pt Graphite
1.B.O.Regan, M. Grätzel, Nature 1991, 353,737-740.
2.Lee, Y. L., Chang.C.H., Journal of Power Sources 2008, 185, 584-588.
3.Nozik, A. J., Beard, M. C., Luther, J. M., Law, M., Ellingson, R. J., and Johnson, C. J., Chemical Reviews 2010, 110, 6863-6890.
4.Veerapana, G., Bojan, K.,and Rhee, S. W., Journal of Ameri, Chem, Society 2010,857-862
5. Hod, I., Pedro, V. G., Tachan, Z., Santiago, F. F., Seró, I. M., Bisquert, J., and Zaban, A., J. Phys. Chem. Lett. 2011, 2, 3032-3035.
6.Guijarro, N., Campiña, J. M., Shen, Q., Toyoda, T., Villarreal, T. L., and Gómez, R., Phys. Chem. Chem. Phys. 2011, 13, 12024-12032.
7. Tennakone, K., Bandara, J., Bandaranayake, P. K. M., Kumara, G. R. A., and Konno, A., Jpn. J. Appl. Phys. 2001, 40, 732-734.