In this study, the physical and chemical degradation behaviors of active layers based on semicrystalline p-type polymer (poly(3-hexylthiophene) (P3HT)) and [6,6]-phenyl C 71 butyric acid methyl-ester (PC 71BM) are compared with the corresponding behaviors of amorphous p-type polymer of poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′, 7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) and PC 71BM. A surface morphological study of the active layer (from Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images) and a chemical analysis (from X-ray photoelectron spectroscopy (XPS) and Energy dispersive X-ray spectroscopy (EDS) results) help explain why PCDTBT/PC 71BM bulk heterojunction (BHJ) has a higher level of long-term stability under thermal and air stability experimental conditions than a P3HT/PC 71BM-based BHJ. The power conversion efficiency for a PCDTBT/PC 71BM BHJ cell and a P3HT/PC 71BM BHJ cell decreased by 11% and 21%, respectively, after a thermal stability test and by 68% and 78%, respectively, after a 300 h air stability test.
Bibliographical noteFunding Information:
This work was supported by a grant from the ERC program ( R11-2007-045–01002-0(2009) ) and NCRC program ( 2011-0006268 ) of National Research Foundation (NRF) funded by the Korea Ministry of Education, Science and Technology (MEST) and also supported by the research program through the NRF of Korea funded by the MEST ( 20110023215, 20110027677 ). J.H. Park acknowledges Future-based Technology Development Program (Nano Fields) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2010-0029321 ). The authors thank Prof. Alan J. Heeger and Jason Seifter at Center for Polymers and Organic Solid in University of California, Santa Barbara for helpful comments, materials and SEM analysis.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films