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 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 | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".