[4]‐Cyclo‐2,7‐Carbazole as Host Material in High‐Efficiency Phosphorescent OLEDs: A New Perspective for Nanohoops in Organic Electronics
Bibliographic record
Abstract
Abstract In the last ten years, the development of π‐conjugated nanohoops has been considerable owing to their remarkable properties. However, to date, their incorporation in organic electronic devices remains very scarce. In this work, the first high‐performance organic electronic device (i.e., phosphorescent organic light‐emitting diode, PhOLED) incorporating a nanohoop ([4]‐cyclo‐N‐butyl‐2,7‐carbazole, [4]C‐Bu‐Cbz) is reported, revealing the potential of nanohoops in electronics. Thus, using the red phosphor Ir(MDQ)2(acac), the [4]C‐Bu‐Cbz‐based PhOLED displays a high external quantum efficiency (EQE) of 17.0%, a current efficiency (CE) of 20.6 cd A−1 and a power efficiency (PE) of 25.8 lm W−1 demonstrating that the charge injection, transport, and recombination are particularly efficient. This performance is significantly higher than that of its linear counterpart, N‐butyl‐2,7‐quartercarbazole ([4]L‐Bu‐Cbz), which presents an EQE of 11.1%, a CE of 13.0 cd A−1 and a PE of 15.7 lm W−1. The significant difference, in terms of device performance, between cyclic and acyclic compounds provides a new basis to construct high‐performance electronic devices. This study, which includes optical, electrochemical, morphological, and charge transport properties, shows that nanohoops can be efficiently used as organic semiconductors in electronics and opens the way to their practical uses in high‐performance optoelectronic devices, which is now the next stage of their evolution.
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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 | 0.000 |
| 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 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".