Synthesis, structural and optical characteristics of Mn and Ag co-doped ZnInS/ZnS Core/Shell Nanocrystals: Tunability of emission from orange to white for LED applications and flexible electronics devices

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2025-05, Vol.462, Article 116206
• Main Authors: Joicy, S., Salman Rashid, K.V., Sivaselvam, S., Thangadurai, P.
• Format: Article
• Language: English
• Subjects: Core/shell; Double-emission; Hot-injection; Nanocrystals; Polymer-NCs composite
• ISSN: 1010-6030
• DOI: 10.1016/j.jphotochem.2024.116206

[Display omitted] •Mn and Ag co-doped ZnInS/ZnS core/shell nanocrystals were synthesized.•The optical bandgap was tuned from 3.72 eV to 4.27 eV.•The core/shell with Mn/Ag = 0.1 showed the highest PL decay lifetime of 425.04 ns.•The emission colour is tuned from orange to white and the CIE color coordinates fall within the warm white light region.•The white emissive Mn,Ag:ZnInS/ZnS NCs could be employed in white quantum dot LEDs. Colloidal Mn and Ag co-doped ZnInS/ZnS core/shell nanocrystals (NCs) with various Mn:Ag ratios were synthesized by a high-temperature organometallic route. Synthesis of core/shell NCs with nontoxic elements, high quantum yield, and high Stokes shift is challenging and presented in this work. They were studied by X-ray diffraction (XRD), photoluminescence (PL), UV–Vis absorption, and time-resolved PL spectroscopies to understand their structural and optical properties. The core and core/shell NCs possessed a ZnS-type cubic zinc-blende crystal structure. The core/shell NCs have shown a tailored optical bandgap ranging from 3.72 eV to 4.27 eV. The ratiometric of Ag+ and Mn2+ dual emissions were tuned by changing the Mn to Ag concentration ratio. The Mn,Ag:ZnInS/ZnS core/shell NCs with Mn to Ag ratio of 0.1 showed the highest PL decay lifetime of 425.04 ns. With appropriate doping, the emission color is tuned from orange to white, and the CIE color coordinates fall within the warm white light region. The Stokes shift was observed to be 183 nm and 293 nm for the Mn and Ag-related emissions, respectively, and therefore, the self-absorption was very much reduced. Further, the core/shell NCs were incorporated into a PMMA matrix with uniform distribution to have a flexible thick film of this blend, and optical properties were studied. The resulting flexible NC-PMMA composite films exhibited high PL emission intensity and moderate transparency in the visible region. The overall results suggested that the white emissive Mn,Ag:ZnInS/ZnS NCs could be employed in white quantum dot light-emitting diode devices so that these NCs have strong potential for white light LED application.