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Large crystalline domains and enhanced exciton diffusion length enable efficient organic solar cells
- Publication Year :
- 2019
- Publisher :
- American Chemical Society, 2019.
-
Abstract
- The authors thank the European Research Council for financial support (EXCITON Grant 321305). We studied crystallinity and exciton harvesting in bulk heterojunctions of a semiconducting polymer PffBT4T-2OD and electron acceptor PC71BM which are used to make highly efficient organic solar cells. Grazing incidence wide-angle X-ray scattering (GIWAXS) shows that the size of crystalline domains of PffBT4T-2OD increases to ~18 nm in photovoltaic blends upon thermal annealing at 100 °C for 5 minutes. These domains are larger than the typical exciton diffusion lengths in conjugated polymers. Time-resolved fluorescence measurements show that exciton diffusion length in PffBT4T-2OD increases from ~14 to ~24 nm upon thermal annealing, which enables efficient charge generation in blends with large domains. Solar cells prepared using thermally annealed blends show higher photocurrent, open circuit voltage and fill factor compared to as spin-coated blends which indicates reduced recombination losses. Our results demonstrate the advantages of large crystalline domains in organic photovoltaics, providing exciton diffusion is sufficient. Postprint
- Subjects :
- Materials science
Organic solar cell
General Chemical Engineering
Exciton
02 engineering and technology
010402 general chemistry
7. Clean energy
01 natural sciences
Crystallinity
Materials Chemistry
QD
SDG 7 - Affordable and Clean Energy
Diffusion (business)
chemistry.chemical_classification
Open-circuit voltage
Scattering
DAS
Heterojunction
General Chemistry
Polymer
QD Chemistry
021001 nanoscience & nanotechnology
T Technology
0104 chemical sciences
chemistry
Chemical physics
0210 nano-technology
Subjects
Details
- Language :
- English
- ISSN :
- 08974756
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....f9b8aea38431a1b1345b4d28714f79ad