Naked-eye-visible electrochemiluminescence from Ag-In-Zn-S quantum dots via core doping and surface copassivation
Ruijie Qin1, Yuzhu Sun1, Mingyue Chen1
1Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin 300350, PR China.
Journal of Colloid and Interface Science
|April 5, 2026
Summary
Environmentally friendly, water-soluble Ag-In-Zn-S quantum dots (QDs) were developed for enhanced electrochemiluminescence (ECL) sensing. These QDs show a 130-fold ECL improvement, enabling sensitive iodide detection in aqueous solutions.
Area of Science:
- Materials Science
- Analytical Chemistry
- Nanotechnology
Background:
- Cadmium/lead-based quantum dots (QDs) are toxic and perform poorly in water.
- Existing electrochemiluminophores (ECLphores) face limitations in biological applications due to toxicity and aqueous instability.
- Developing eco-friendly, water-soluble ECLphores is crucial for advanced analytical sensing.
Purpose of the Study:
- To create high-performance, environmentally friendly, water-soluble quantum dots for electrochemiluminescence (ECL) applications.
- To enhance the ECL efficiency and photoluminescence quantum yield (PLQY) of Ag-In-S-based QDs.
- To demonstrate the utility of these novel QDs in sensitive and selective analytical detection.
Main Methods:
- Synthesized Ag-In-S-based QDs directly in aqueous phase.
- Employed dual-ligand copassivation with glutathione (GSH) and polyethyleneimine (PEI) for surface defect suppression.
- Incorporated Zn2+ into the QD core for doping, relieving lattice strain and improving shell growth.
- Utilized tri-n-propylamine (TPrA) as a coreactant for ECL measurements.
Main Results:
- Achieved a photoluminescence quantum yield (PLQY) of up to 71.5% for the synthesized QDs.
- Demonstrated a 130-fold enhancement in electrochemiluminescence (ECL) efficiency compared to pristine Ag-In-S QDs.
- Obtained intense near-infrared ECL emission at 710 nm, visible to the naked eye in aqueous solution.
- Successfully detected iodide (I-) with a low detection limit of 3.2 nM, showcasing sensitive and selective sensing capabilities.
Conclusions:
- Developed a dual-enhancement strategy (surface copassivation and core doping) for high-performance Ag-In-Zn-S (AIZS) quantum dots.
- AIZS QDs offer a promising, eco-friendly alternative to toxic heavy-metal QDs for ECL applications.
- The enhanced ECL properties enable sensitive and selective detection of analytes in aqueous media, with potential for biological sensing.
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