Hole Transport Molecules in High <i>T</i><sub>g</sub> Polymers: Their Effect on the Performance of Organic Light-Emitting Diodes
Bibliographic record
Abstract
Two high T g transparent polymers, A435 and CH, have been synthesized to be used as host materials for TPD, a hole transport molecule that is morphologically unstable when vacuum-sublimed as a thin film. A435 forms solid solutions with TPD in all proportions while TPD is only soluble in CH up to about 30 wt %. At higher contents in CH, TPD forms microscopic clusters. Films containing up to 75 wt % TPD in A435 or CH are morphologically stable when heated at 100 °C for 72 h. OLED devices have been made using variable TPD contents in A435 or CH as a hole transport layer and Alq 3 as an electroluminescent and electron transport layer. The best OLED performance is obtained for 75 wt % TPD in A435 ( L max ∼ 3500 cd/m 2; η max ∼ 0.8%) and in CH ( L max ∼ 6000 cd/m 2; η max ∼ 1.7%). The difference in performance has been mainly attributed to the electron transport capability of A435, which is not an electrically inactive host polymer like CH. In devices made with A435, electrons are able to reach the ITO electrode where they neutralize without participating in the electroluminescence of the device. When this electron leakage is blocked with a thin CuPc layer, L max and η max of devices made with A435 + TPD or CH + TPD become practically identical. Device performance is therefore indifferent to the particular physical state (solid solution or microclusters) of the hole transport molecules in the host polymer. The electron transport capability of A435 has been demonstrated using a device comprising a first layer of pure A435 spin-coated on top of a layer of high T g polymer, STPD-QP, showing bipolar transport properties and luminescence in the blue.
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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 | 0.001 | 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) | 0.000 | 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".