Phase-Pure Crystalline Zinc Phosphide Nanoparticles: Synthetic Approaches and Characterization
Bibliographic record
Abstract
Zinc phosphide may have potential for photovoltaic applications due to its high absorptivity of visible light and the earth abundance of its constituent elements. Two different solution-phase synthetic strategies for phase-pure and crystalline Zn 3 P 2 nanoparticles (∼3–15 nm) are described here using dimethylzinc and vary with phosphorus source. Use of tri- n -octylphosphine (TOP) with ZnMe 2 takes place at high temperatures (∼350 °C) and appears to proceed via rapid in situ reduction to Zn(0), followed by subsequent reaction with TOP over a period of several hours to produce Zn 3 P 2 nanoparticles. Some degree of control over size was obtained through variance of the TOP concentration in solution; the average size of the particles decreases with increasing TOP concentration. With the more reactive phosphine, P(SiMe 3 ) 3, lower temperatures, ∼150 °C, and shorter reaction times (1 h) are required. When P(SiMe 3 ) 3 is used, the reaction mechanism most likely proceeds via phosphido-bridged dimeric Zn(II) intermediates, and not metallic zinc species, as is the case with TOP. In all cases, the nanoparticles were characterized by a combination of X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and solution and solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) analyses. Surface investigation through a combination of MAS 31 P NMR and XPS analyses suggests that the particles synthesized with TOP at 350 °C possess a core–shell structure consisting of a crystalline Zn 3 P 2 core and an amorphous P(0)-rich shell. Conversely, the ligand and phosphorus sources are decoupled in the P(SiMe 3 ) 3 synthesis, resulting in significantly reduced P(0) formation.
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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".