A combined study of mesomorphism, optical, and electronic properties of donor-acceptor columnar liquid crystals
Bibliographic record
Abstract
Donor-acceptor structures have recently gained great popularity for the design of low band gap polymeric organic semiconductors. Presented here is a first systematic study of organic semiconductors based on columnar liquid crystals that consist of discotic and board-shaped donor-acceptor structures. The discotic benzotristhiophenetricarboxamide and hexaphenyldiquinoxalinophenazine derivatives form hexagonal columnar mesophases over wide temperature ranges while the board-shaped tetraphenylquinoxalinophenanthrophenazine derivative displays rectangular and hexagonal columnar mesophases. All compounds are designed to preferentially conduct electrons and not holes because the central acceptor parts, which are the sole contributors to the unoccupied frontier orbitals, show strong intermolecular electronic interactions within columnar stacks whereas the donor parts at the periphery of the cores, the sole contributors to the occupied frontier orbitals, are too far apart to provide sufficient electronic interactions. The absence of hole conduction is confirmed by charge carrier mobility measurements based on time-resolved microwave conductivity and time-of-flight methods that reveal intrinsic electron mobility values of about 10-2 cm2 V-1 s-1. The board-shaped compound is also highly fluorescent not only in solution but also in its mesophases. Interstingly, the fluorescence quantum yield of its mesophases reversibly increases with decreasing temperature, which is reasoned with changes in molecular mobility and intracolumnar packing within columnar stacks.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 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 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".