Abstract
Conjugated polymers and small molecules based on alternating electron-donating (D) and electron-accepting (A) building blocks have led to state-of-the-art organic solar cell materials governing efficiencies beyond 10%. Unfortunately, the connection of D and A building blocks via cross-coupling reactions does not always proceed as planned, which can result in the generation of side products containing D-D or A-A homocoupling motifs. Previous studies have reported a reduced performance in polymer and small molecule solar cells when such defect structures are present. A general consensus on the impact of homocouplings on device performance is, however, still lacking as is a profound understanding of the underlying causes of the device deterioration. For differentiating the combined effect of molecular weight and homocouplings in polymer solar cells, a systematic study on a small molecule system (DTS(FBBTh2)2) is presented. The impact of homocouplings on nanomorphology, thermal, and electro-optical properties is investigated. It is demonstrated that small quantities of homocouplings (
Original language | English |
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Journal | Chemistry of Materials |
Volume | 28 |
Issue number | 24 |
Pages (from-to) | 9088-9098 |
Number of pages | 11 |
ISSN | 0897-4756 |
DOIs | |
Publication status | Published - 2016 |
Keywords
- Chemical reactions
- Conjugated polymers
- Defects
- Electronic properties
- Molecules
- Nanostructured materials
- Optical properties
- Organic polymers
- Organic solar cells
- Polymer solar cells
- Batch-to-batch variations
- Cross coupling reactions
- Device performance
- Electrooptical properties
- Photoactive layers
- Small molecule systems
- Solar cell materials
- Solution processable
- Solar cells