Bulk Heterojunction Photovoltaic Cells from Polymer Mixtures with Soluble Oxadiazole and Quinoline Polymers as Electron
- PDF / 338,627 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 63 Downloads / 194 Views
L5.16.1
Bulk Heterojunction Photovoltaic Cells from Polymer Mixtures with Soluble Oxadiazole and Quinoline Polymers as Electron Acceptors Solon Economopoulos[1,2], Christos L. Chochos[1,2], Giannis K. Govaris[1,3], Panagiotis Yiannoulis[3], Joannis K. Kallitsis[1,2] and Vasilis G. Gregoriou[1]* [1] Foundation for Research and Technology Hellas Institute of Chemical Engineering and High Temperature Chemical Processes, (FORTH-ICEHT), P.O. Box 1414, Patras 26504, Greece. [2] Department of Chemistry, University of Patras, Patras 26500 Greece. [3] Department of Physics, University of Patras, Patras 26500 Greece. * Corresponding author. Phone: (+30)2610-965205. Fax: (+30)2610-965223. E-mail: [email protected] ABSTRACT The interplay between phase separation in polymer blends consisting of the electron donating poly(3-hexylthiophene-2,5-diyl) (P3HT) or poly[2-methoxy-5-(2’-ethylhexyloxy)-,4phenylenevinylene] (MEH-PPV), with either polyquinoline or a fluorene-oxadiazole copolymer as the electron accepting polymers is presented herein. The bulk heterojunction photovoltaic performance has been examined for these blends along with a new copoly(aryl ether) containing substituted anthracene and fluorene segments coupled with aromatic 1,3,4-oxadiazole moieties. Photoluminescence quenching in the MEH-PPV blends as well as a 100-fold photocurrent enhancement of the bulk heterojunction device P3HT/SDPQ photovoltaic device were observed compared to the single layer P3HT device. Finally, the structure and morphology of these films was investigated using atomic force microscopy and scanning electron microscopy in an attempt to correlate the role of morphology to photovoltaic performance. INTRODUCTION Since the discovery of electroluminescence in conjugated polymers [1], this class of materials has been used to build efficient light emitting diodes, field effect transistors, photodetectors and photovoltaic diodes. The discovery of photoinduced electron transfer in composites of conjugated polymers and buckminsterfullerene, C60 [2] provided an efficient molecular approach for improved photovoltaic conversion (up to 3%). In general, increased conversion efficiencies can be accomplished through improvement of the charge carrier generation, selective charges transportation and collection and light harvesting. Although polymeric photovoltaic devices have been mainly based on the C60 as the electron acceptor[3], the use of polymers as both the electron donor and acceptor offers many advantages. The energy gaps and ionization potentials of conjugated polymers can be finely tuned through chemical modification of the polymeric structure. Indeed, purely polymeric photovoltaic cells with high efficiencies have been reported, in which distributed heterojunctions on a nanometer scale provided effective dissociation of excitons. Conjugated polymers containing quinoline or oxadiazole moieties are characterized by high thermal stability, outstanding mechanical properties, and can form optically clear films. Their electroluminescent and photocond
Data Loading...
