Abstract
We investigate a correlation between the type of solvent additives (SAs) with specific criteria such as aromatic additives (AAs) and non-aromatic additives (NAAs) and phase separation in the bulk heterojunction (BHJ) films comprising low-band gap polymer and fullerene derivatives. When AAs are used as SAs, the geometrical structures (π-π and lamellar stacking) of aggregated polymer chains do not significantly change. However, NAAs increase the lamellar stacking distance through a strong interaction with non-aromatic segments of polymers. Therefore, a well-phase separated BHJ morphology with the finer fibrils is developed, thereby leading to balanced charge mobilities and a reduced charge recombination in BHJ solar cells. Finally, the optimized solar cell exhibits a high power conversion efficiency of 7.9%.
Original language | English |
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Pages (from-to) | 200-207 |
Number of pages | 8 |
Journal | Nano Energy |
Volume | 30 |
DOIs | |
State | Published - 1 Dec 2016 |
Keywords
- Bulk heterojunction solar cells
- Low-band gap polymer
- Phase separation
- Solvent additives