Exciton Lifetime Broadening and Distribution Profiles of PbS Colloidal Quantum Dot Thin Films Using Frequency- and Temperature-Scanned Photocarrier Radiometry
Bibliographic record
Abstract
Photocarrier radiometry (PCR) has been applied to PbS colloidal quantum dot (CQD) thin films for the absolute measurement of emission lifetimes. Continuous and discrete models describing lifetime distribution have been developed. The former yields homogeneous and inhomogeneous Voigt lifetime broadening. The latter comprises two models: one is based on direct ad hoc fits to PCR amplitude and phase data, reconstructing a superposition of multiple independent lifetime line spectra; the other is a variational method developed to invert simultaneous integral equations in the lifetime distribution function (spectrum) and involves similar fits to the PCR in-phase and quadrature signal channels to reconstruct the lifetime spectrum. A PCR theory with a rate equation model taking into account the lowest 1S–1S exciton state splitting and multiphonon-assisted carrier trapping to states outside a PbS QD was also developed. For noninteracting (uncoupled) CQDs, longitudinal optical (LO) phonon–exciton interactions limit the radiative lifetime and luminescence photon flux throughout the entire 100–300 K temperature range. For interacting (coupled) CQDs, variational and ad hoc lifetime line spectra exhibit similar mechanisms to uncoupled CQDs with the important addition of direct exciton-to-exciton transitions in the form of efficient transport (hopping, tunneling, or FRET) at all temperatures, which result in de-excitation dynamics dominated by radiative emission channels.
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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) | 0.000 | 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".