Rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control

• Published in: Nano research Vol. 13; no. 9; pp. 2438 - 2450
• Main Authors: Soares, José X., Wegner, K. David, Ribeiro, David S. M., Melo, Armindo, Häusler, Ines, Santos, João L. M., Resch-Genger, Ute
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01.09.2020; Springer Nature B.V
• Subjects: Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Cadmium; Chemical composition; Chemistry and Materials Science; Condensed Matter Physics; Design; Design optimization; Emissions control; Materials Science; Mathematical models; Nanotechnology; Parameter identification; pH effects; Photoluminescence; Photons; Quantum dots; Reaction time; Research Article; Silver; Synthesis; Toxicity; Zinc sulfide; microwave-assisted synthesis; quantum dot; silver indium sulfide; design of experiment; photoluminescence; core/shell nanoparticle
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-020-2876-8

In the blossoming field of Cd-free semiconductor quantum dots (QDs), ternary I-III-VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water, their high photoluminescence (PL) quantum yields (QYs) in the red and near infrared (NIR) region, and their inherently low toxicity. Moreover, their oxygen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications exploiting the compound-specific parameter PL lifetime. To overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties, we assessed and modelled the synthesis of high-quality MPA-capped AgInS 2 /ZnS (AIS/ZnS) QDs. Systematically refined parameters included reaction time, temperature, Ag:In ratio, S:In ratio, Zn:In ratio, MPA:In ratio, and pH using a design-of-experiment approach. Guidance for the optimization was provided by mathematical models developed for the application-relevant PL parameters, maximum PL wavelength, QY, and PL lifetime as well as the elemental composition in terms of Ag:In:Zn ratio. With these experimental data-based models, MPA:In and Ag:In ratios and pH values were identified as the most important synthesis parameters for PL control and an insight into the connection of these parameters could be gained. Subsequently, the experimental conditions to synthetize QDs with tunable emission and high QY were predicted. The excellent agreement between the predicted and experimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AIS/ZnS QDs with defined PL features. This approach can be straightforwardly extended to other ternary and quaternary QDs and to doped QDs.