Bathochromic shift in photo-absorption spectra of organic dye sensitizers through structural modifications for better solar cells

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Contributed Talks at Australian Institute of Physics 20th National Congress (under the theme of Energy, Energy Materials and Energy Systems), December 2012, Sydney …

Contributed Talks at Australian Institute of Physics 20th National Congress (under the theme of Energy, Energy Materials and Energy Systems), December 2012, Sydney

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  • 1. Narges Mohammadi, Feng Wang
  • 2. Global need for energy isestimated to be doubledby 2050 and triplet by theend of this century.Fossil fuels?-Limited-Environmental concernsSolar ?-Readily available-Abundant-CleanCurrent silicon-based solarcells?-ExpensiveDye sensitized solar cells:-Cost-effective alternative forthe photovoltaic energy sectorIntroduction2
  • 3. 3Leaf-shaped transparent DSSC with fourcolors courtesy AISIN SEIKI CO.,LTD.These (DSSC) windows generate powerfrom indoor lighting and ambient light. Inthis demonstration, the electricitygenerated is used to spin a propellercourtesy Sony Japan.Translucent DSSCs in four coloursenliven these lanterns. The powergenerated is stored in a built-inbattery that illuminates the lampbulb. No external power is usedcourtesy Sony Japan.Conventional Silicon PV vs. DSSCRoof-mounted conventional siliconsolar panels.DSSCs can be made with dyes of differentcolours courtesy TDK Japan.
  • 4. Transparent ElectrodeCounter ElectrodeTiO2TiO2|S + hv → TiO2|S∗TiO2|S* → TiO2|S+ + e−cbS+ +3/2 I- →S+1/2 I3-1/2 I3- +e(pt)- →3/2 I-HOMOLUMODye Sensitizere-e-e-e-e-e-e-e-e-e-e-I3- 3I-DSSC Working Scheme4
  • 5. 5Research Question• Dye-sensitized solar cells absorb >85% ofvisible light, but almost no light in the near-infrared.400 600 800 1000 120001x10182x10183x10184x10185x1018Photons/(nmm2s)Wavelength (nm)AMA 1.5VisiblelightInfraredLightSolar Spectrum• How rational and in silico design can be exploited in the design of neworganic dye sensitizers for the application of dye sensitized solar cells .
  • 6. Rational design for new organic dyes which possess : Broader and red-shifted absorption band. Reduced HOMO-LUMO gap. Suitability for the application of solar cells. Dye SensitizerHOMOLUMO6Objectives
  • 7. 7Methods & Computational DetailsSelection of well-performing dyes as the backbone of the study.Chemically modifying the dye structure through substitutions ondifferent position of dye.Optimize the molecule structure using DFT methods. (B3LYP,PBE0)To obtain the HOMO-LUMO energy levels and other relatedproperties.Simulation of UV-Vis spectra using TD-DFT.Suggestion to synthesis chemists through collaboration.TheoryLevel:Densityfunctionaltheory (DFT)TimedependantDFT(TDDFT)Packages:Gaussian09Gaussview,Molden,GaussSum,ChemissianComputational Details
  • 8. TA-St-CA DyeFig.2: Experimental and calculated UV-Visspectra of TA-St-CA dye in ethanolsolution.Fig.1: TA-St-CA* structure.* Hwang, S., et al., Chem. Commun, 46: p. 4887-4889,(2007).8
  • 9. New Dyes (NP)9Fig.4: NP3 Fig.5: NP6Fig.6: NP7 Fig.7: NP10Fig.3: TA-St-CA
  • 10. New Dyes (NP)10Fig.9: UV-Vis spectra of newlydesigned dyes and TA-St-CA dye invacuum.Fig.8: Calculated orbital energydiagrams of the dyes using the PBE0/6-311G(d) model.
  • 11. 11Carbz-PAHTDTT DyeFigure 10: Sketch of Carbz-PAHTDTT* dye and its derivatives.* Daeneke, T., et al., “High-efficiency dye-sensitized solar cells with ferrocene-based electrolytes”, Nat Chem, 3(3): p. 211-215, (2011).
  • 12. 12Energy(eV)-1.5-2-2.5-3-3.5-4-4.5-5-5.5-62.55 2.06 2.36Carbz-PAHTDDT D1 D2Figure 11: Calculated frontierMO energy levels in vacuum.Figure 12: Isodensity surfaces of HOMO andLUMO for Carbz-PAHTDDT dye and derivativedyes D1 and D2.Carbz-PAHTDTT Dye
  • 13. 13Carbz-PAHTDTT DyeFigure 13: UV-Vis absorbance spectra of Carbz-PAHTDDT dye and derivative dyes D1 and D2.
  • 14. -Swinburne university vice-chancellorspostgraduate award.-Victorian partnership for advancedcomputing, VPAC, for supercomputingfacilities.-Prof. F. Wang and A/Prof .P. Mahonfor their supervision, guidance,encouragement, and support.
  • 15. THANK YOU!