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Record W2049306737 · doi:10.1021/jp803845n

Multiple Families of Magic-Sized CdSe Nanocrystals with Strong Bandgap Photoluminescence via Noninjection One-Pot Syntheses

2008· article· en· W2049306737 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueThe Journal of Physical Chemistry C · 2008
Typearticle
Languageen
FieldMaterials Science
TopicQuantum Dots Synthesis And Properties
Canadian institutionsSteacie Institute for Molecular SciencesInstitute for Microstructural Sciences
Fundersnot available
KeywordsPhotoluminescenceNanocrystalMolar ratioFull width at half maximumBand gapCadmium acetateMaterials scienceAnnealing (glass)ColloidMolar concentrationNanotechnologyCrystallographyChemical engineeringNuclear chemistryAnalytical Chemistry (journal)ChemistryCadmiumPhysical chemistryCatalysisOrganic chemistryOptoelectronicsMetallurgy

Abstract

fetched live from OpenAlex

Three families of colloidal CdSe magic-sized nanocrystals (MSNs) exhibiting bright bandgap photoluminescence (PL) with narrow full width at half-maximum (fwhm) on the order of ca. 10 nm were synthesized in pure form. This noninjection one-pot synthetic approach uses cadmium acetate dihydrate (Cd(OAc) 2 ·2H 2 O) and elemental selenium as Cd and Se source compounds, respectively, while a fatty acid as surface ligands and 1-octadecene (ODE) as the reaction medium. All of these chemicals were loaded at room temperature in a reaction flask, with low acid-to-Cd and high Cd-to-Se feed molar ratios; the growth of the CdSe MSNs was carried out at 120 −240 °C. This synthetic approach allows long growth/annealing periods at high temperature and thus results in high-quality CdSe MSNs exhibiting strong bandgap PL; furthermore, this ready approach features high synthetic reproducibility and large-scale production. The reason for the low acid-to-Cd feed molar ratio is argued to be related to the low activity of the Cd precursor in the form of Cd(OAc) x (OOC−(CH 2 ) n −CH 3 ) 2− x, which releases Cd slowly. The reason for the high Cd-to-Se feed molar ratio is also addressed to help prevent the dissociation of the formed CdSe MSNs. Furthermore, short ligand and low temperature favors the formation of small MSNs, while long ligand and high temperature favors large MSNs. Regarding our synthetic approach, these MSN families can coexist together with one regular nanocrystal ensemble which is larger in size; in such a case, they develop independently from different nuclei; the small MSN families can dissociate into monomers to feed the formation of other MSN families and/or the regular nanocrystal ensemble. The three MSN families exhibit sharp bandgap absorption at 395, 463, and 513 nm, within the size range of 1.7−2.2 nm by diffusion ordered NMR spectroscopy (DOSY).

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.001
Threshold uncertainty score0.396

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.001
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.023
GPT teacher head0.219
Teacher spread0.196 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it