Switchable Crystal Phase and Orientation of Evaporated Zinc Phthalocyanine Films for Efficient Organic Photovoltaics
Bibliographic record
Abstract
In photovoltaic cells, increasing the light absorption coefficient enhances the photocurrent and quantum efficiency of the cell. Here, we report an efficient approach that enhances light absorption by changing the crystal phase of an evaporated ZnPc film on indium tin oxide (ITO) substrates. Under thermal treatment (>200 °C), the crystal phase of ZnPc changed from metastable α-ZnPc to stable β-ZnPc. We tested and compared the effects of this phase transition on the donor film of organic photovoltaic (OPV) cells. After treating the β-ZnPc film at 220 °C, the short-circuit current of the OPV was improved from 2.58 to 3.40 mA/cm 2, and the quantum efficiency was improved from 650 to 750 nm. Moreover, on a copper iodide (CuI)–ITO substrate, the ZnPc molecules were precisely controlled in the lying-down orientation. With their lying-down orientations, the light absorbance capacities of the metastable α-ZnPc phase and stable β-ZnPc phase (annealed at 300 °C) were 1.3- and 1.5-fold higher, respectively, than that of metastable α-ZnPc standing upright on the ITO substrate. This work provides a fundamental understanding of the crystal phases and orientation changes of the ZnPc molecules, enabling maximization of the light absorption coefficient and the design of efficient small-molecule OPV 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) | 0.001 | 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".