Tuneable blue-green co-activated CaAl2O4: 0.1 mol% Tb3+, x mol% Sm3+ (0 ≤ x ≤ 2) nanophosphor prepared by citrate sol-gel method
Why this work is in the frame
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Bibliographic record
Abstract
This study reports the analysis of tuneable blue-green phosphor of calcium aluminate (CaAl2O4) co-doped with terbium (Tb3+) and varying concentration of samarium (Sm3+) (0 ≤ x ≤ 2). The powder samples were synthesized by using the citrate sol-gel method and annealed at 900 °C for 2 h (h) for all samples. The X-ray powder diffraction (XRD) results revealed a developing amorphous monoclinic structure of CaAl2O4. Co-doping with Tb3+ and Sm3+ slightly affected the structure of synthesized CaAl2O4. Scanning electron microscope (SEM) results showed that co-doping the host material of CaAl2O4 slightly affected the morphology of the synthesized nanopowders. The transition electron microscope (TEM) images showed that the particle sizes of the host material were affected by doping. Ultraviolet–visible (UV–Vis) reflection spectroscopy suggested that the band gap of co-doped CaAl2O4:0.1 mol% Tb3+, x% Sm3+ (0 ≤ x ≤ 2) ranges between 5.05 and 5.20 eV. The photoluminescence (PL) results showed several emission peaks located at 420, 440, 484, 548, 558, 562, 584, 603 and 654 nm. Emission peaks at 420, 440, 484 and 558 nm were attributed to the host material. The peaks at 548 and 558 nm are originating from 5D4→7F6 and 5D4→7F5 transitions of Tb3+ while the peaks at 562, 603 and 654 nm seems to be originating from the dopant of Sm3+ which may be assigned to 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, and 4G5/2 → 6H9/2 transitions of Sm3+, respectively. CIE coordinates results suggested that the emission colour can be tuned from bluish to greenish as x% Sm3+ concentration is varied.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.008 | 0.007 |
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 it