Electron Dynamics at the Surface of Semiconductor Nanocrystals
Bibliographic record
Abstract
Semiconductor nanocrystals emit light from excitons confined to their core, as well as from their surfaces. Time-resolving the emission from the core yields information on the band edge exciton, which is now well understood. In contrast, the emission from the surface is ill-characterized and remains poorly understood, especially on long time scales. In order to understand the kinetics of charge trapping to the surface and electronic relaxation within the surface, we perform time-resolved emission spectroscopy on CdSe nanocrystals with strong surface emission. The time-resolved spectra reveal a time scale of electron transfer from core to surface much slower than previously thought. These spectra also unveil electron dynamics in the surface band, which gives rise to an average lifetime spectrum. These dynamics are explained by invoking two surface states. This simple model further rationalizes the role of ligands in tuning the surface emission of nanocrystals. These experimental results provide a critical test of our understanding of the electronic structure of the surface.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.001 | 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 teacher head, 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".