Organic Solar Cells. Active material is much cheaper to produce than Si. Easily deposited as thin films over large (flexible) areas

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1 Research activities on organic photovoltaics at the Center of Innovation and Research in MAterials and Polymers CIRMAP University of Mons Roberto Lazzaroni Journée scientifique des comices Energie solaire amur 23/04/2012

2 Organic olar Cells Active material is much cheaper to produce than i University of Linz 2004 Easily deposited as thin films over large (flexible) areas Power Plastic, Konarka, 2007

3 Power Conversion Efficiency April 2012

4 Organic solar cell structure Gilles Dennler, KOARKA [ev] vs vacuum DOOR p" ACCEPTOR n" ITO PEDOT P Al V oc is set by (acc) (don)

5 Materials for organic photovoltaics Conjugated polymers mall molecules RO OR n Poly(p-phenylenevinylene), PPV C 60 H H RO OR phthalocyanine n Polythiophene, PT * Thin film deposition from solution * (spin coating, inkjet printing,dr.blading, ) H O O perylene Deposition by vacuum sublim. into highly-ordered thin films O O H * Wide range of chemical substitution Molecular engineering * Chemical purity

6 Research activities on organic photovoltaics at CIRMAP - UMO CIRMAP: Center of Innovation and Research in MAterials and Polymers Four research groups : ~ 100 research staff ervice de Chimie des Matériaux ouveaux CM: R. Lazzaroni ervice des Matériaux Polymères et Composites MPC : Ph. Dubois Laboratoire Interfaces et Fluides Complexes Influx: P. Damman CHimie des Interactions Plasma-urfaces ChIP: R. nyders Design and modeling of materials and photophysical processes: CM Tailored synthesis of polymer semiconductors: MPC Thin film morphology and electrical properties : CM Microstructured layers for light management: Influx ovel materials for electrodes: ChIP In close collaboration with - Materia ova (P. Viville et al) : device fabrication and testing - ULB (Y. Geerts), UCL (. Melinte), ULg (C. Jérôme),

7 Organic solar cell : light absorption Gilles Dennler, KOARKA [ev] vs vacuum DOOR p" ACCEPTOR n" ITO PEDOT P Al

8 Efficiency of light conversion 25% of the incoming solar light is harvested for a gap of 2.1 ev.. ariciftci, Materialstoday, eptember 2004 AM1.5 conditions Total photon flux Photon flux MEH-PPV Integrated photon flux Wavelength (nm) Light harvesting at higher wavelengths is essential

9 Design de molécules low bandgap : 2 e génération E DOEUR Donneur Accepteur Mélange donneur-accepteur transfert d électron voltage Molécule Low bandgap accepteur Calcul des propriétés électroniques et optiques par les méthodes de chimie quantique

10 Couples donneur-accepteur Donneurs Donneurs T T-TB 2TT Influence de la structure? 2TB 2TB-TB 2TC-TB Influence du pont ethynylene? 2TT-TB O O O O EDOT EDOT-TB 2TC Accepteurs Accepteurs QX (quinoxaline) TQX (thiazolo[3,4- g]quinoxaline) BT (bezothiadiazole) TDA Influence de la structure?

11 iveaux énergétiques: Donneurs 2TB 2TB EDOT EDOT-TB 2TC 2TC-TB 2TT 2TT-TB T T-TB Energy (ev) La triple liaison abaisse la sans toucher à la Pas de diminution du voltage final

12 iveaux énergétiques: Accepteurs -1 QX BT TQX TDA Energy (ev) L accepteur TQX présente la la plus basse

13 Conclusions élection des meilleurs couples donneur-accepteur 2TB TQX E

14 Introduction Controlled synthesis of P3HT via GRIM mechanism McCullough, R. D. et al. Acc. Chem. Res. 2008, 41, Yokozawa, T. et al. J. Am. Chem. oc. 2005,,

15 Tuning the optical and electronic properties by the block copolymer approach ilole-based conjugated block copolymers Poly(4,4-dihexyl-4H-silolo[3,2:b-4,5:b ]dithiophene)-b-poly(3-hexylthiophene) P2 C 6 H 13 I THF 30 min 0 C Br iprmgcl Br 1/ iprmgcl Br 2/ i(dppp)cl 2 n i THF, overnight, 4 C i C 6 H 13 C 6 H 13 C 6 H 13 C 6 H 13 C 6 H 13 ClMg Br THF, overnight, 4 C i C 6 H 13 C 6 H 13 n C 6 H 13 m B1 P2 Entry i/3ht* M n GPC (g/mol) Ð λ max (nm) 1 23/ , / ,1 596 (*) as determined by 1 H MR

16 ilole-based (co)polymers : optical absorption properties C 6 H 13 n i C 6 H 13 C 6 H 13 n i C 6 H 13 C 6 H 13 n C 6 H 13 m P3HT P1 P2 The block copolymer has a broader absorption spectrum

17 Organic solar cell : charge generation Gilles Dennler, KOARKA [ev] vs vacuum DOOR p" ACCEPTOR n" ITO PEDOT P Al V oc is set by (acc) (don)

18 Binary donor-acceptor systems for organic PV Electron donors Electron acceptors O O n n H H PPV or PT derivatives PCBM O Perylene O Ionization potential is small energy Electron affinity is large energy (+ hole transport) (+ electron transport) All organic PV devices are two-component systems Charge separation takes place at the D-A interface

19 Electronic structure at the donor/acceptor interface ADT/C 60 ADT/C 70 ADT/PTCDI L of the acceptor Together eparated Together eparated Together eparated H of the donor At 4 Å, there is no big shift of the and levels of the donor and the acceptor due to the polarization effect. with Y. Geerts at al. Opt: DFT (B3LYP/6-31G(d,p))

20 Organic solar cell: charge transport Gilles Dennler, KOARKA [ev] vs vacuum DOOR p" ACCEPTOR n" ITO PEDOT P Al

21 Modeling the supramolecular organisation and charge transport properties RO OR H H R = (CH 2 ) 12 (CH 2 ) 9 CH 3 CH 3 RO OR 1D tatic stack: µ= cm²/ V s Dynamic stack: µ=0.17 cm²/ V s Increase in charge carrier mobilities due to dynamical motion with Y. Geerts at al.

22 Carbon nanotubes as additives to favor charge transport in organic photovoltaic cells Pyrene-functionalized P3HT to favor CT dispersion in conjugated polymer matrix

23 ynthesis of P3HT-pyrene copolymer Monomer Grignard Metathesis (GRIM) block copolymerization Grafting of pyrene along the chain

24 Modeling the nanotube/ conjugated polymer interface P3HT chains interacting with a WT The P3HT fibrils tend to arrange perpendicular to CT axis

25 Research activities on organic photovoltaics at CIRMAP - UMO CIRMAP: Center of Innovation and Research in MAterials and Polymers Four research groups : ~ 100 research staff ervice de Chimie des Matériaux ouveaux CM: R. Lazzaroni ervice des Matériaux Polymères et Composites MPC : Ph. Dubois Laboratoire Interfaces et Fluides Complexes Influx: P. Damman CHimie des Interactions Plasma-urfaces ChIP: R. nyders Design and modeling of materials and photophysical processes: CM Tailored synthesis of polymer semiconductors: MPC Thin film morphology and electrical properties : CM Microstructured layers for light management: Influx ovel materials for electrodes: ChIP In close collaboration with - Materia ova (P. Viville et al) : device fabrication and testing - ULB (Y. Geerts), UCL (. Melinte), ULg (C. Jérôme),