Role of Photon Recycling and Band Filling in Halide Perovskite Photoluminescence under Focussed Excitation Conditions
Bibliographic record
Abstract
We study the temporal, spatial, and spectral evolution of charge carriers in hybrid perovskite thin films after optical excitation with a small laser spot. These are conditions typical of microscopy-based studies. After excitation, the spreading of charge carriers in space occurs due to a combination of diffusion, recombination, and photon recycling. To quantitatively understand their relative importance, a numerical model is used to simulate the anticipated photoluminescence (PL) while accounting for these processes. We also experimentally study the evolution of the PL spectrum at different radial positions from the center of the excitation spot. This allows us to extend our previous work on carrier diffusion performed using time-resolved PL microscopy. Our numerical model predicts a position-dependent spectral shift of the waveguided photon energy in agreement with previous reports. However, we show that the spectral shift under our experimental conditions is dominated by band filling. Finally, we study the interplay between pump spot size, diffusion constant, and fluence on carrier transport in the presence of photon recycling. Our results show that in typical micro-PL experiments and modest carrier densities, photon recycling plays a negligible role in enhancing the lateral spreading of carriers.
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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".