Solarzellen. Funktion & Anwendung. NREL Chart (5/2017) Dye Sensitized Solar Cells (DSSC) Solid State Dye Sensitzed Solar Cell (SS DSSC, Grätzel)

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1 Funktion & Anwendung Solarzellen Modul F&A, SS NREL Chart (5/2017) Sensitized Solar Cells (DSSC) Grätzel Zelle Ru 3 4 Sensitized Solar Cells (DSSC) Solid State Sensitzed Solar Cell (SS DSSC, Grätzel) 5 6 1

2 in amorphous solids Vergleich Grätzel Zellen (flüssig vs. fest) Hopping NHE I 2 /I 3 Spiro MeOTAD V max by diffusion 7 D. Hertel, H. Bässler, ChemPhysChem 2008, 9, Short Introduction OPV device structure Electron donors MDMO PPV [1], PCE = 2.5% PC 60 BM Electron acceptors Processing VAC SOL 2001 P3HT [2], PCE = % bis PC 60 BM [5] D A 2003 PC 70 BM General device structure PCPDTBT [3], PCE = 5.1% PEDOT:PSS 2006 PCDTBT [4], PCE = 6.1% [1] Appl. Phys. Lett. 2001, 78, 841. [2] Adv. Funct. Mater. 2003, 13, 85. BHJ Bulk heterojunction PHJ Planar heterojunction 2009 [3] Adv. Mater. 2006, 18, [4] Nature Photonics 2009, 3, 297. [5] Adv. Mater. 2008, 20, Organic Solar Cells Photocurrent Generation bulk planar heterojunction (BHJ) (PHJ) electron collecting contact (ECC) acceptor + + donor hole + collecting contact (HCC) h substrate active layer energy h 4. + hole collecting contact donor acceptor 4. electron collecting contact Einschicht Solarzelle Bulk Heterojunction (BHJ) Akzeptor Zweischicht Solarzelle Planare Heterojunction (PHJ) 1. Exciton generation / diffusion 2. Exciton dissociation 3. Free charge carrier generation / 4. Charge extraction 11 Donor 12 2

3 Device Architecture Vergleich Grätzel Zelle vs. Inorganic: Organic: p n junction donor acceptor junction VAC LUMO (D) LUMO (A) BiLayer Heterojunction Bulk Heterojunction (BHJ) Halls et.al., Nature 376, 498 (1995) Yu et.al., Science 270, 1789 (1995) Structured Heterojunction vacuum deposition solution processing theoretical NHE Spiro MeOTAD Donor HOMO (D) Acceptor HOMO (A) V max Primary Processes in solar cell (dark = OLED) Comparison Primary Processes in OPVs & OLEDs Charge injection (+) Holes at anode ( ) Electrons at cathode (+) Holes on HOMO ( ) Electrons on LUMO (+) + ( ) Formation of Exciton Light emission Sigulett Triplett Light extraction Solar Cell, OPV Charge extraction (loss) Charge separation Formation of Exciton Light absorption Light coupling OLED Charge injection Formation of Exciton Light emission Light absorption (loss) Light extraction

4 Solar Spectrum Hell Dunkel Kriterien Solarzelle Woran kann man drehen? Hohe Effizienz (> 10%) Hohe Voc HOMO(D) LUMO(A) Hoher Jsc Hoher FF Mobilität Morphologie Hohe Absorption Extinktionskoeffizient Lamda_max Temperaturbeständigkeit ( 40 bis +85C) Lebensdauer Reinheit der verwendeten Substanzen Verkapselung Verklebung (Grätzel Zelle) (System) Kosten Reproduzierbarkeit Hohe Effizienz (> 10%) Hohe Voc HOMO(D) LUMO(A) Hoher Jsc Hoher FF Mobilität Morphologie Hohe Absorption Extinktionskoeffizient Lamda_max Temperaturbeständigkeit ( 40 bis +85C) Lebensdauer Reinheit der verwendeten Substanzen Verkapselung Verklebung (Grätzel Zelle) (System) Kosten Reproduzierbarkeit Systems Approach in Organic Photovoltaics Solarzellen basierned auf Merocyaninen FW & KM, 16, 9366 (2010) 4

5 Organic Solar Cells based on Merocyanine s Organic Solar Cells based on Merocyanine s Merocyanines (MC) low molecular weight colorants textile coloration printing nonlinear optics DSSC [F. Würthner, R. Wortmann, K. Meerholz, JACS 123, 2810 (2001).] [S. Uchida and M. Grätzel, Adv. Mater. 18, (2006).] easily tunable absorption (UV NIR): adjustment to the solar irradiation. MD352 MD333 EL086 HB238 MD357 HB239 e donating sub unit conjugation e accepting sub unit increasing acceptor strength Indoline Aminothiophene (Dioxocyano) Pyridine (Dicyanomethylene) Indanone (Dicyanomethylene) Thiazol A = acceptor sub unit D = donor sub unit Possible Molecular Arrangements Screening of Merocyanine s (SOL Processing) Goal: Structure Property Relations 27 FW & KM, 16, 9366 (2010) 28 N. Kronenberg, H. Bürckstümmer Screening, Milky Way (SOL) (Frustrating) Conclusion Al V OC /V J SC /ma cm Active layer PEDOT:PSS ITO FF WEAK dye interaction E HOMO * /ev % PCE N. Kronenberg, H. Bürckstümmer E HOMO * /ev Some correlation with E HOMO * (dye interaction / aggregation) STRONG dye interaction Determination of Structure Property Relations very difficult 30 5