POLYMER BASED PHOTOVOLTAICS

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1 PLYMER BASED PHTVLTAICS Novel concepts, materials and state-of-the-art performances Jan Kroon

2 Semiconducting polymers Nobel Prize Chemistry 2000 (Alan J. Heeger, Alan G. MacDiarmid, Hideki Shirakawa) Conducting polymers Plastic batteries Polymer light-emitting diodes and lighting Polymer lasers Plastic transistors and integrated circuits Polymer displays Polymer memories Polymer detectors and sensors Polymer solar cells..... and much more to come!

3 Polymer PV Potential cheap, simple and fast (roll-to-roll) processing flexible and lightweight tuneable properties, multi-color design create new application possibilities (e.g. PV integrated in products powering wearable electronics, PV coated glass, etc.) Challenges - High efficiencies (>10 %) and long term stability achievable?

4 rganic p/n heterojunction electron transfer TC p-type n-type + metal absorption - donor acceptor exciton dissociation into + and charge carriers C. W. Tang, Appl. Phys. Lett. 1985, 48, 183.

5 The need for a Bulk Heterojunction (BHJ) Essence: enlargement of the interface effective charge separation + - mixture D-A materials phase separation bicontinuous network selective electrodes Active interface nm

6 Polymer fullerene Polymer PV Research routes Highest efficiencies so far Relatively poor spectrum use Polymer polymer Potentially better spectrum use Polymer inorganic Control of morphology High electron mobilities

7 Polymer : fullerene state-of of-the art MDM-PPV C 60 PCBM ( ) n Me I 0 V C = 0.87 V η = 2.5 % V J (ma/cm 2 ) -2-4 FF = J SC = 4.9 ma/cm 2 Jeroen van Duren et al., Adv. Funct. Mater. 12, 2002, Sean Shaheen et al., APL, 78 (2001), 841 Voltage (V) Jan Kroon et al., TSF, (2002), 223

8 Change of acceptor: from C60 to C70 Me MDM-PPV ( ) n C 70 PCBM EQE wavelength / nm [70]PCBM (DCB) [60]PCBM (CB) Jsc/mAcm η = 3.0 % η = 2.5 % Voltage/V Martijn Wienk, Jan Kroon, Kees Hummelen et al., Angew. Chem. Int. Ed. 2003, 42,

9 Change of donor Postproduction treatment (annealing) of P3HT:PCBM solar cells C 6 H 13 S n Me I sc = 8.7 ma/cm 2 V oc = 580 mv FF = 0.55 η e = 2.8%. Pavel Schilinsky et al., Appl. Phys. Lett. 2002, 81, 3885 Franz Padinger et al., Adv. Funct. Mater 2003, 13, 85 annealing at 75 C gives 3.5% cells

10 Morphology P3HT : PCBM blends after deposition after annealing at 110 C for 60 min increasing crystallinity Xiaoniu Yang et al., Nano Lett. 2005, 5,

11 Long term stability Device integrity (hermetic sealants, barrier coatings) (Photo)chemical stability of materials, interfaces AND Stable morphology of a two-component blend MPP S C 6 H 13 n Me hours ECN Test conditions 1 sun illumination in N 2 atmosphere T cel = 70 o C

12 Polymer : polymer BHJ Challenge: High conductive, light absorbing n-type polymers C 10 H 21 Efficiency (%) EQE (%) wavelength (nm) H 3 C + S R1 CN R2 R2 NC Me S n Year Collaboration of ECN, TN

13 Polymer : inorganic nanocomposites Challenge: Produciblity of efficient polymer/nanocrystal blends Combinations of polymers (PPV,P3HT) with: inorganic light absorbing nanostructures: nanodots, nanorods and tetrapods Metal oxides: Ti 2 and Zn nanostructures η = % Zn nanorods

14 utlook Polymer PV Future research issues Polymer PV Jsc: - new low band gap polymers - morphology control Voc: - optimizing energy levels - electrode engineering Stability: - morphology control - photo (chemistry) Device developments: Wavelength (nm) - substrates, (transparent) electrodes, light trapping, stacking, integration, Upscaling - materials, fabrication technologies (profiting from organic electronics experiences) Photons in Electrons out

15 Route towards commercialisation? efficiency lifetime costs R&D Siemens 2004 Consumer applications Portables, novelties time High power applications?

16 Acknowledgments ECN Wil-Jan Verhees Sjoerd Veenstra Lenneke Slooff TU Delft Tom Savenije Pieter Quist TN Science & Industry Marc Koetse Jolanda Bastiaansen Jörgen Sweelssen Herman Schoo TU Eindhoven Paul van Hal Martijn Wienk Waldo Beek René Janssen Xiaoniu Yang Joachim Loos RU Groningen Joop Knol Minze Rispens Kees Hummelen Valentin Michailetchi Paul Blom All the international partners!!