Effect of Acceptor Unit Length and Planarity on the Optoelectronic Properties of Isoindigo–Thiophene Donor–Acceptor Polymers
Bibliographic record
Abstract
Conjugated polymers with a donor–acceptor (DA) structural motif have found extensive use in a wide variety of optoelectronic devices; however, despite their ubiquity in the literature, the vast majority of these materials are simple alternating copolymers—one electron donor alternates with one electron acceptor in the polymer backbone. As a result, the impact of composition (e.g., donor/acceptor ratio) and structure (e.g., alternating, block, or random) on the optoelectronic properties of these copolymers remains poorly understood. In this work, the number of acceptor units in alternating DA copolymers is systematically increased. Two dimers of the common electron acceptor isoindigo are synthesized, one with free rotation between the subunits and one with enforced coplanarity. The two dimers are then used to synthesize donor–acceptor–acceptor (DAA) copolymers with either thiophene or terthiophene comonomers. These DAA polymers feature two electron acceptors in their repeat unit, and their optoelectronic properties are compared to those of the analogous DA polymers. It is shown that increasing the number of acceptor units causes a decrease in the LUMO energy of the resulting polymer; this effect is enhanced by enforcing coplanarity between acceptor units via ring fusion. All six polymers were tested in both organic photovoltaics (OPVs) and organic thin film transistors (OTFTs). While the DA polymers performed better in OPVs, the DAA polymers displayed more balanced charge carrier mobilities in OTFTs.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".