Novel Stable Blue-Light-Emitting Oligofluorene Networks Immobilized by Boronic Acid Anhydride Linkages
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Bibliographic record
Abstract
Thermal dehydration of boronic acid groups to form six-membered boronic acid anhydride (boroxine) was employed as a means of immobilizing oligofluorenes. This approach appears to improve the photoluminescenct stability of the cross-linked films compared to polyfluorenes. The emergence of long-wavelength emission upon thermal treatment usually observed in polyfluorenes has been prevented in this system. Initially the fluorene dimer ( F2BA ), trimer ( F3BA ), and tetramer ( F4BA ) containing boronic acid groups were prepared. These compounds were found to be readily soluble in common solvents such as THF, acetone, and DMF. Transparent thin films of these materials could be easily prepared by casting their solutions in THF onto KBr disks or glass substrates. Using mild reaction conditions (60−130 °C under vacuum for 2 h), these oligomers in the solid sate readily undergo cross-linking reactions by the dehydration of boronic acid groups as evidenced by FT-IR spectroscopy and DSC/TGA studies. The resulting cross-linked amorphous networks exhibit high thermal ( T d at 5% weight loss, 363−420 °C) and morphological ( T g, 173−202 °C) stability. Under UV irradiation, these compounds emit bright violet-blue ( F2BA ) and blue ( F3BA and F4BA ) light both in solution and in the solid state. The cured films exhibited almost identical UV−vis and fluorescence spectra even after heating at 150 °C for 24 h, showing no long wavelength emission. The fabrication of LED devices using F3BA or F4BA as the light-emitting layer and a carbazole diboronic acid ( CzBA ) as the hole-transporting layer demonstrated that these thermally curable diboronic acids can be used to achieve double- (or multi-) layered configurations.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 it