Concentration-Dependent Photoinduced Photoluminescence Enhancement in Colloidal PbS Quantum Dot Solution
Bibliographic record
Abstract
The concentration-dependent photoinduced photoluminescence (PL) enhancement of PbS quantum dots (QDs) is observed for the first time in the PbS colloidal solution. The enhancement in PL efficiency is attributed to the photooxidation of PbS QD surface based on the optical, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) measurements. The decrease in PbS QD concentration leads to the increase in the amplitude of PL enhancement and to the decrease in the time required to reach the maximum PL enhancement. For the lowest investigated QD concentration of 58.7 nmol/L, PL efficiency can be increased by as much as 60 times. The critical concentration for realizing the considerable PL enhancement is found to be ∼200 nmol/L. Further investigation shows that the concentration-dependent PL enhancement is related to spontaneous ligand desorption and therefore more efficient photooxidation in low-concentration samples. Furthermore, it was found that the enhanced PL can remain during storage. It suggests that the postsynthesis treatment of UV illumination can serve as an alternative, while simple and highly efficient way in improving the PL efficiency of PbS QDs when the coverage of surface ligands is appropriately controlled.
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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 | 0.000 | 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 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".