Effect of Molecular Shape on the Properties of Non-Fullerene Acceptors: Contrasting Calamitic Versus 3D Design Principles
Bibliographic record
Abstract
The recent development of high-performance nonfullerene acceptors has relied on two main design principles: the calamitic design, where side chains are arranged orthogonally to a planar chromophore, and the 3D design, where the chromophore is forced to adopt a nonplanar structure. Until now, there has been no direct comparison of these designs. In this work, small molecule nonfullerene acceptors with both the calamitic design ( FBRCN ) and the 3D design ( XFBRCN ) were synthesized. These molecules bear the same chromophore unit and have similar solubilities. Our results show that the 3D semiconductor XFBRCN has a higher extinction coefficient, broader absorbance bands, and a higher permittivity than the calamitic FBRCN . This is due to the lower crystallinity and better polarizability of the 3D acceptor. In contrast, the calamitic FBRCN had a higher electron mobility, was more miscible with polymeric OPV donors, and was more crystalline than the 3D XFBRCN . This is attributed to the long alkyl chains of FBRCN encouraging efficient solid-state packing. This work highlights the differences between the two material design principles, and helps to elucidate the role of side chains in controlling film morphology and the performance of solid-state electronic devices.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".