Donor–acceptor alternating copolymers containing thienopyrroledione electron accepting units: preparation, redox behaviour, and application to photovoltaic cells
Bibliographic record
Abstract
Four new donor–acceptor semiconducting alternating copolymers consisting of thienopyrroledione (TPD) electron-accepting sub-units and either 2,7-carbazole or dialkoxy substituted benzodithiophene electron-donating moieties were prepared either by Suzuki or Stille coupling. Analytical size exclusion chromatography (SEC) was used to fractionate the copolymer with 1 : 1 thienopyrroledione to carbazole ratio into 9 sharp fractions. The effective conjugation length (35 aromatic rings) was determined on the basis of the dependence of λmax of the π–π* band on the degree of polymerization, DPn. All four polymers showed similar supramolecular organization resembling that of poly(3-alkylthiophene)s since the mechanism of the self-assembly was the same in both cases: π-stacking of the π-conjugated polymer backbones and interdigitation of n-alkyl side chains. As shown by cyclic voltammetry studies, three copolymers showed band gaps inferior to 2 eV with HOMO and LUMO levels ranging between −5.62 eV to −5.08 eV and −3.53 eV to −3.13 eV, respectively. UV-vis-NIR spectroelectrochemical investigations confirmed the results obtained by cyclic voltammetry, enabling in addition more precise determination of the HOMO level. Raman spectroelectrochemical studies showed that the polymer with 1 : 1 thienopyrroledione to carbazole ratio is prone to oxidative degradation, consistent with cyclic voltammetry studies. A bulk-heterojunction solar cell was fabricated from the copolymer consisting of thienopyrroledione and dialkoxy substituted benzodithiophene. A power conversion efficiency of 1.63% was achieved for non-optimized devices.
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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".