Zinc octacarboxyphthalocyanine / Multi-walled Carbon Nanotubes Hybrid for the Development
of Dye Solar Cells
Nonhlanhla Mphahlele
Materials Science & Manufacturing: Energy & Processes (EaP) 7 September 2010
OUTLINE
• INTRODUCTION
• OBJECTIVES
• EXPERIMENTAL PROCEDURE
• RESULTS AND DISCUSSION
• CONCLUSION
• ACKNOLEGEMENTS
• FUTURE PLANS
OUTLINE OF PRESENTATION
• INTRODUCTION
• OBJECTIVES
• EXPERIMENTAL
• PRELIMINARY RESULTS
• CONCLUSIONS
• FUTURE WORK
Dye solar cells prepared from our group
Solar simulator
2010 www.csir.co.za
INTRODUCTION
The choice of the sensitisers
N NCS
NCS
COOH HOOC
COOH
Ru
N NCS
NCS
COOH HOOC
COOH
Ru
N N
N
N NCS
NCS
COOH HOOC
COOH
Ru
N NCS
NCS
COOH
HOOC HOOC
COOH
Ru
N N
N
N NCS
NCS
COOH HOOC
COOH
Ru
N NCS
NCS
COOH HOOC
COOH
Ru
N N
N
N NCS
NCS
COOH HOOC
COOH
Ru
N NCS
NCS
COOH
HOOC HOOC
COOH
Ru
N N
N
Zinc octacarboxyphthalocyanine
N
N NH
Porphyrins NH
Introduction Cont’d
Zn
N N
N
N N N
N N
HOOC COOH
COOH
COOH
HOOC COOH HOOC
HOOC
N3 dye
Introduction cont’d
• WHY CNTs?
* High thermal stability
* High surface area
* Excellent electrical conductivity
OBJECTIVES
• The main aim is to improve the cell
performance and the long term stability of
DSCs by utilizing dye (metallophthalocyanines) that absorb light at Visible region, integrated with carbon nanotubes to increase the
stability and conductivity.
2010 www.csir.co.za
CO CO
CO CO
O O
N N
N
N N N
N N
Zn N H
O O
O O
N H
O O
N H
O
O
NH
N
HOOC COOH N N
N
COOH
COOH N N
HOOC COOH
N HOOC
HOOC
N
Zn
KOH/ 100°C - 8hrs Zn (CH3CO2)2
(NH2)2CO/DBU
Synthetic Route of ZnOCPCs
2010 www.csir.co.za
H2SO4/HNO3
SOCl2 24hr
Cl O O
N
NH2
Amine-functionalised MWCNTs
2010 www.csir.co.za
H2N
NH2
5 days
O
OH H2SO4/ H2O2
H
2010 www.csir.co.za ZnOPC
Red OX hv
e e
V
Pt catalyst TiO2
TCO TCO
MWCNTs ZnOCPC
Schematic of ZnOCPc/MWCNT Hybrids in DSC
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
300 400 500 600 700
Absorbance
wavelength,nm
ZnOCPc and its precursor
ZnOCPc and its precursor
MWCNT-NH2 MWCNT-COOH
Preliminary Results cont’d
TECHNIQUES INFORMATION GATHERED EXAMPLE
UV/Vis To identify the absorption spectra of ZnOPC
B-band ~350nm Q-band~690nm FTIR To determine functional groups
present in ZnOPC and MWCNTs
Carboxylic acid - ZnOPCs C=O ~ 1740-1680 cm-1 OH ~ 3400-3000cm-1 (broad peak)
Amide -MWCNTs
N-H ~ 3450-3100 cm-1 (secondary-assigned with one peak)
C=O~1690-1630cm-1
TEM Investigate internal structure of MWCNT-ZnPC
XRDs Investigate the crystallinity of a- MWCNT, a-MWCNT-ZnOCP c nanocomposite
PRE LIMINARY RESULTS
Preliminary Results cont’d
•Figures show MWCNTs after treated with acid and also integrating the ZnOPC/ MWCNT nanocomposite
0 1000 2000 3000 4000 5000 6000
10 20 30 40 50 60
intensity (a.u)
Angle (2theta)
0 1000 2000 3000 4000 5000 6000
20 25 30 35 40 45 50 55 60
Angle (2theta)
intensity (a.u)
20 30 40 50 60
intensity (a.u)
Angle(2theta)
C (002) C (100)
C (002) C (100)
Untreated MWCNT Acid-treaed MWCNT
ZnOCPc/MWCNT
• Figures show MWCNTs after each stage of the
functionalisation step
• Increase in the metallic content noticed (dark spots)
• Suggests that
functionalisation process was successful
• Need to do high-resolution TEM to further investigate the surface/interface between MWCNT and ZnOPC
Untreated MWCNT
Acid-treated MWCNT
MWCNT-NH2
ZnOCPc/MWCNT-NH2
Preliminary Results cont’d
CONCLUSIONS
• Managed to synthesised ZnOCPc and it was confirmed by UV/Vis. Performed the
treatment of MWCNTs
• Integrated the ZnOCPc/MWCNTs and applied in DSC, tested using the solar simulator
2010 www.csir.co.za
FUTURE WORK
• Characterisation of treated MWCNTs – SEM, XRD
• Characterisation of ZnOPC-MWCNTs-XPS, TGA, XRD, EDX
• Full DSC studies
• Visit to Japan to make Ti-based MPc
2010 www.csir.co.za
Acknowledgements
• Dr Ken Ozoemena
• Dr Lukas Le Roux
• Dr Mkhulu Mathe
• Dr Leskey Cele (TUT supervisor)
• CSIR for sponsoring the project
• All my colleagues at the EaP, CSIR
2010 www.csir.co.za
2010 www.csir.co.za
