Effect of Eu3+ concentration on the structure and photoluminescence properties of the BaAl2O4/MgAl2O4/BaCO3:x% Eu3+ (0 ≤ x ≤ 1.5) mixed phases synthesized by citrate sol-gel method
Bibliographic record
Abstract
We report the structural, morphological and photoluminescence properties of BaAl 2 O 4 /MgAl 2 O 4 /BaCO 3 :x% Eu 3+ (0 ≤ x ≤ 1.5) mixed phases (hereafter called BMB:x% Eu 3+ ) synthesized by a citrate sol–gel method. X-ray diffraction confirms the coexistence of hexagonal BaAl 2 O 4 , cubic MgAl 2 O 4 and orthorhombic BaCO 3 phases; indexed XRD patterns are presented. Scanning and transmission electron microscopy show an Eu 3+ -dependent morphological evolution from nanorods to irregular crystallites. Photoluminescence spectra (λ ex = 226 and 268 nm) reveal defect-related bands in the undoped BMB (centred at 550 nm) and sharp Eu 3+ 5 D 0 → 7 F J transitions in doped samples. The Eu 3+ -activated emission intensity at 620 nm is maximized at x = 1.1 % (optimal concentration), above which concentration quenching reduces intensity. Spectral deconvolution and lifetime reanalysis (bi-exponential fits) indicate energy transfer from host defect states to Eu 3+ and the involvement of at least two Eu 3+ environments. Colour coordinates shift from green to orange-red with increasing Eu 3+ concentration. These findings identify composition and morphology conditions for optimized orange-red emission in the BaAl 2 O 4 /MgAl 2 O 4 /BaCO 3 mixed-phase phosphors.
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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 | 0.001 |
| 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".