Bisisoindigo–Benzothiadiazole Copolymers: Materials for Ambipolar and n-Channel OTFTs with Low Threshold Voltages
Bibliographic record
Abstract
The development of design strategies in both ambipolar and electron-conducting organic thin-film transistor (OTFT) materials is important for producing high-performance materials and devices in organic electronics. Isoindigo donor–acceptor polymers have been well studied as hole-conducting materials in OTFTs, while more electron-deficient, acceptor-rich isoindigo polymers have been underexplored. In this report, two common design strategies in isoindigo-based polymers, acceptor–acceptor polymers and core-expanded isoindigo structures, are combined to create copolymers of bisisoindigo, a core-expanded derivative of isoindigo, and electron-deficient benzothiadiazoles. These polymers exhibit the low energy lowest unoccupied molecular orbitals (LUMOs) required for electron transport and show ambipolar OTFT performance with hole and electron mobilities up to 4.0 × 10 –3 and 1.4 × 10 –3 cm 2 V –1 s –1, respectively. Additionally, changing the source and drain contacts from Au to LiF/Al significantly lowered the threshold voltage due to improved alignment of the polymer and electrode energy levels. Comparisons of the optoelectronic properties between these polymers and previously reported bisisoindigo donor–acceptor polymers indicate that the increased acceptor strength lowers the frontier molecular orbital energies, while the dithienyl-benzothiadiazole unit impacts the film morphology by altering the shape of the polymer backbone.
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) | 0.001 | 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".