Localized Gradual Photomediated Brightness and Lifetime Increase of Superacid-Treated Monolayer MoS<sub>2</sub>
Bibliographic record
Abstract
Monolayer semiconducting transition-metal dichalcogenides (S-TMDs) have been extensively studied as materials for next-generation optoelectronic devices due to their direct band gap and high exciton binding energy at room temperature. Under a superacid treatment of bis(trifluoromethane)sulfonimide (TFSI), sulfur-based TMDs such as MoS 2 can emit strong photoluminescence (PL) with a photoluminescence quantum yield (PLQY) approaching unity. However, the magnitude of PL enhancement varies by more than 2 orders of magnitude in published reports. A major culprit behind the discrepancy is sulfur-based TMD’s sensitivity to above-bandgap photostimulation. Here, we present a detailed study of how TFSI-treated MoS 2 reacts to photostimulation with increasing PL occurring hours after continuous or pulsed laser exposure. The PL of TFSI-treated MoS 2 is enhanced up to 74 times its initial intensity after 5 h of continuous exposure to 532 nm laser light. Photostimulation also enhances the PL of untreated MoS 2 but with a much smaller enhancement. Caution should be taken when probing MoS 2 PL spectra, as above-bandgap light can alter the resulting intensity and peak wavelength of the emission over time. The presence of air is verified to play a key role in the photostimulated enhancement effect. Additionally, the rise of PL intensity is mirrored by an increase in measured carrier lifetime of up to ∼400 ps, consistent with the suppression of nonradiative pathways. This work demonstrates why variations in PL intensity are observed across samples and provides an understanding of the changes in carrier lifetimes to better engineer next-generation optoelectronic devices.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".