Spectral and Photophysical Properties of Fluorene-Based Polyesters in Solution and in the Solid State
Bibliographic record
Abstract
The optical and photophysical properties of fluorene-based polyesters in solution and in the solid state (thin films) are reported. The red-shifted emission bands observed in the photoluminescence spectra of the thin films are rationalized in terms of stronger π−π intermolecular interactions due to the closeness of the molecules (molecular packing) in the solid state. This is further corroborated by time-resolved fluorescence decay measurements. However, these electronic interactions are not strong enough to induce excimer or aggregate formation. As such, the quenching excimer and/or aggregate deactivation channel found in many polymeric systems are less efficient in the present polyesters. As expected, the presence of ester linkages between adjacent oligomers causes an interruption of the electronic conjugation, thus limiting the fluorescence to the blue region. The fluorescence efficiencies of thin films, estimated from lifetime measurements of the polyesters in solution and in the solid state, are relatively high (10−25%). Hence, these materials are promising candidates in the fabrication of blue-emitting LED 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 | 0.001 |
| 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".