Bathochromic shift in photo-absorption spectra of organic dye sensitizers through structural modifications for better solar cells
Narges Mohammadi, Feng Wang
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
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.
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 .
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
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
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
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.
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).
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
13Carbz-PAHTDTT DyeFigure 13: UV-Vis absorbance spectra of Carbz-PAHTDDT dye and derivative dyes D1 and D2.
-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.