Alkyl Side Chain Impact on the Charge Transport and Photovoltaic Properties of Benzodithiophene and Diketopyrrolopyrrole-Based Copolymers
Bibliographic record
Abstract
To investigate the side chain effect on the photovoltaic performance of conjugated copolymers with alternating electron push–pull structures, three alternating copolymers (O–HD, BO–BO, and PU–O) of benzodithiophene and dithienyldiketopyrrolopyrrole were designed and synthesized. They were nomenclated based on the side chains on the benzodithiophene (BDT) and the diketopyrrolopyrrole (DPP) units, which are octyl (O) and 2-hexyldecyl (HD); 3-butyloctyl (BO), and 2-butyloctyl (BO): and 3-pentylundecyl (PU) and octyl (O) groups, respectively. The total C number of the side chains in each repeat unit was kept at 48 to control the dilute effect. The solubility, optical, and electrochemical properties, and crystalline structure of the polymers were depended on the combination of these linear or branched alkyl chains. Thin film transistor (TFT) characterization showed that PU–O had the best hole mobility up to 1.6 × 10 –3 cm 2 V –1 s –1 . The best photovoltaic performance was observed from O–HD with power conversion efficiency (PCE) up to 4.1%. However, it only showed a modest hole mobility of 3.8 × 10 –4 cm 2 V –1 s –1, about 4-fold lower than PU–O. This dramatically different performance of these polymers for TFT and photovoltaic devices was explained by the interaction at the interface of the polymer electron donor and the PCBM acceptor domains.
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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".