Excited-State Behavior of Nile Blue H-Aggregates Bound to SiO<sub>2</sub>and SnO<sub>2</sub>Colloids
Bibliographic record
Abstract
The spectroscopic characterization of a cationic dye, Nile Blue A (NB), in negatively charged SnO 2 and SiO 2 colloidal suspensions has been carried out. The results show that NB, in the presence of these colloidal suspensions, forms aggregates of H-type which are nonfluorescent and have blue-shifted absorption compared to the NB monomer in aqueous solution. Laser photolysis experiments have been carried out to study the excited-state dynamics of the NB aggregates. The transient absorption measurements of NB adsorbed on SiO 2 colloids (inert support) show that the H-aggregates of NB have a relatively short-lived excitonic singlet state (τ = 40 ps); the lifetime of the excited singlet of the monomer in aqueous solution is ∼390 ps. On a reactive semiconductor support like SnO 2, the NB aggregates also inject electrons into SnO 2 . This is characterized by the formation of the cation radical, (NB) 2 • +, of the NB aggregates and by the trapping of electrons the in SnO 2 nanocrystallites. The monophotonic dependence of the formation of (NB) 2 • + on SnO 2 surface supports the charge transfer from NB aggregates to SnO 2 . The rate constant for this heterogeneous electron-transfer process is ∼3.3 × 10 8 s - 1 .
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 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 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".