Control of Conjugation Length and Enhancement of Fluorescence Efficiency of Poly(<i>p</i>-phenylenevinylene)s via Post-halogenation
Bibliographic record
Abstract
Post-functionalization of poly( p -2,5-dihexyloxy−phenyelenevinylene) ( DHO − PPV ) was studied using N -bromosuccinimide (NBS) and N -chlorosuccinimide (NCS) in CHCl 3 and CHCl 3 /AcOH to control the color of fluorescence emission and to enhance emission efficiency. It was found that in addition to electrophilic substitution on phenylene rings, halogen and succinimide (in CHCl 3 ) and acetate groups (in CHCl 3 /AcOH) add across the main chain vinylene groups. With low NXS/PPV reaction ratios (0.1−0.35), where X = Br or Cl, the resulting polymers show poor solubility, a red shift of the absorption maximum, and a decrease in the solid-state fluorescence efficiency (Φ fl ), which are explained on the basis of enhanced interchain interactions. For NXS/PPV reaction ratios between 0.5 and 0.75, the solubility of polymers was significantly improved and Φ fl was enhanced by up to 150% due to exciton confinement and a reduction in chain aggregation. For NXS/PPV reaction ratios >0.75, Φ fl decreased dramatically because of an increasing loss of π-conjugation.
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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) | 0.000 | 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".