Lifetime Enhancement of Visible Light Induced Photocharges in Tungsten and Nitrogen<i>in situ</i>Codoped TiO<sub>2</sub>:WN Thin Films
Bibliographic record
Abstract
We report on one-step in situ codoped TiO 2 thin films synthesized by cosputtering. The purpose of this acceptor–donor passivated codoping approach is to overcome the optoelectronic limitations that arise for monodoped TiO 2 in photocatalytic applications. To evaluate these added benefits, the TiO 2:WN thin films were characterized by different techniques. X-ray diffraction patterns and X-ray photoelectron spectral analysis revealed that both N and W dopants are mostly present in the desired substitutional locations. Additionally, the codoping approach was found to reduce the internal strain and defect density of the TiO 2:WN films as compared to their monodoped TiO 2:N counterparts. This defect reduction is confirmed via photocharge lifetime variation obtained using visible light flash photolysis time-resolved microwave conductivity measurements (FP-TRMC). Photocharge lifetime analysis indicated the presence of three distinct decay processes: charge trapping, recombination, and surface reactions. These characteristic lifetimes of the codoped TiO 2:WN films (i.e., 0.08, 0.75, and 11.5 μs, respectively) were found to be about double those of their nitrogen monodoped TiO 2:N counterparts (i.e., 0.03, 0.35, and 6.8 μs), quantitatively confirming the effective passivating outcome of the tungsten–nitrogen codoping approach developed here. The practicality of this method was confirmed by integrating the TiO 2:WN films as photoanodes for the electro-photocatalytic, solar light driven degradation of a real pollutant (i.e., atrazine). A significant increase in the degradation kinetics, leading to a 4-fold increase in the pseudo-first-order degradation constant for the optimally doped TiO 2:WN photoanodes (0.106 min –1 ) from the undoped TiO 2– x ones (0.026 min –1 ), is a direct consequence of the increased photocharge lifetimes in tandem with visible light photosensitivity.
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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) | 0.001 | 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 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".