Triarylamino and Tricyanovinyl End-Capped Oligothiophenes with Reduced Optical Gap for Photovoltaic Applications
Bibliographic record
Abstract
Novel low optical gap, p-type semiconducting oligothiophenes asymmetrically end-capped with triarylamino and tricyanovinyl groups, PhN-OFOT( n )-TCN ( n = 2, 3), have been synthesized and characterized for photovoltaic applications. With an incorporation of a tricyanovinyl accepting group to the triarylamine, the optical energy gap greatly reduces to 1.46 eV and the LUMO level lowers to 3.9 eV. The initial studies of the bilayer heterojunction PV cells based on the newly developed tricyanovinyl-substituted chromophores as a donor material and C 60 as an acceptor material showed a PCE up to 1.33% with a large open-circuit voltage of 0.82 V in the annealed devices which makes this class of materials promising for further development. Our findings also suggest for the first time that the tricyanovinyl group is highly efficient to lower the LUMO level and reduce the optical energy gap of a p-type semiconducting photosensitizer. It is interesting to find that PhN-OFOT(2)-TCN showed better device performance in bilayer solar cells than PhN-OFOT(3)-TCN although the latter has a slightly narrower optical gap. Since the LUMO energy level of PhN-OFOT(3)-TCN (ca. 3.9 eV vs vacuum) is too close to that of C 60 (4.0 eV), the yield of photoinduced charge carriers was low, leading to a low power conversion efficiency. Our findings highlight the importance of a large LUMO level offset between electron donors and acceptors to the achievement of high performance organic solar cells.
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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".