Tuning Intra and Intermolecular Interactions for Balanced Hole and Electron Transport in Semiconducting Polymers
Bibliographic record
Abstract
Abstract Charge transport in conjugated polymers depends critically on the chemical structure of the polymer chain, morphology, aggregation, and the complex microstructure in the solid state. Recently, molecular planarity and intramolecular electron transport were associated with J-type aggregation, while coplanar stacking and intermolecular hole transport were correlated with H-type aggregation. This fundamental observation suggests that the degree of H- or J-aggregation could be a handle to tune carrier mobility toward desirable device performances. Here, we use a diketopyrrolopyrrole copolymer as a model semiconducting polymer and tune the type and degree of aggregation through film thickness. Optical absorption measurements, grazing incidence wide angle X-ray scattering, and polarized optical microscopy reveal that thin films compose mainly fibrelike J-aggregated structures, and as the films become thicker, the degree of crystallinity and H-aggregation increase. Thickness-dependent charge mobility values, extracted from corresponding organic field effect transistors, confirm that J-aggregated polymer chains are generally preferable for electron mobility, while polymer crystalline H-aggregates support better hole transport. To obtain perfectly balanced ambipolar OFETs, we optimize the microstructure through film thickness and reduce contact resistance by inserting an interlayer of mixed additives at the organic/contact interfaces. A complementary-like voltage inverter combining two identical ambipolar DPP-T-TT OFETs with a common gate as the input voltage and symmetrical performance confirms that DPP copolymers are a promising candidate for applications in ambipolar devices and integrated circuits.
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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) | 0.000 | 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".