Core-Localized Cu Dopants Pin Red Emission in Multinary Ag-Based Quantum Dots.
basic_science · Level V
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- Record sourced from PubMed, PMID 42097131.
- Also identified by DOI 10.1021/acs.nanolett.6c01715.
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Abstract
Alloy-disordered I-III-VI quantum dots often trade spectral stability for efficiency, limiting photon-transport devices through reabsorption. Here, we confine Cu(I) dopants inside Ag-In-Ga-S cores during GaS<sub><i>x</i></sub> overgrowth, verified by Cu-valence fingerprints and quantitative elemental mapping showing predominantly core-enriched Cu distribution, and obtain red emission spectrally pinned with a constant Stokes shift (∼140 meV) across growth and maturation. Single-dot spectroscopy resolves symmetric Lorentzian lines down to ∼62 meV, showing that the broad ensemble band is dominated by population inhomogeneity rather than an intrinsically broad dopant transition. First-principles calculations identify substitutional Cu<sub>Ag</sub> as a low-energy defect forming an acceptor-like, Cu-S <i>p</i>-<i>d</i> hybridized valence-edge manifold, rationalizing the pinning. The resulting dots deliver photoluminescence quantum yields up to 85% and enhance luminescent solar concentrators to an optical efficiency of 7.33% by mitigating reabsorption.