Molecularly Resolved Electronic Landscapes of Differing Acceptor–Donor Interface Geometries
Bibliographic record
Abstract
Organic semiconductors are a promising class of materials for numerous electronic and optoelectronic applications, including solar cells. However, these materials tend to be extremely sensitive to the local environment and surrounding molecular geometry, causing the energy levels near boundaries and interfaces essential to device function to differ from those of the bulk. Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STM/STS) have the ability to examine both the structural and electronic properties of these interfaces on the molecular and submolecular scales. Here, we investigate the prototypical acceptor–donor system, 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA)/copper(II) phthalocyanine (CuPc) using submolecularly resolved pixel-by-pixel STS to demonstrate the importance of subtle changes in interface geometry of prototypical solar cell materials. PTCDA and CuPc were sequentially deposited on NaCl bilayers to create lateral heterojunctions that were decoupled from the underlying substrate. Donor and acceptor states were observed to shift in opposite directions, suggesting an equilibrium charge transfer between the two. Narrowing of the gap energy compared to isolated molecules on the same surface is indicative of the influence of the local dielectric environment. Further, we find that the electronic state energies of both acceptor and donor are strongly dependent on the ratio and positioning of both molecules in larger clusters. This molecular-scale structural dependence of the electronic states of both interfacial acceptor and donor has significant implications for device design, where level alignment strongly correlates to device performance.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".