Double-shelling AgInS₂ nanocrystals with GaS _x /ZnS to make them emit bright and stable excitonic luminescence

Abstract

This paper presents the successful synthesis of AgInS2 nanocrystals (NCs) double-shelled with GaSx and ZnS for emitting bright and narrow excitonic luminescence from AgInS2 core NCs. Additionally, the AgInS2/GaSx/ZnS NCs with a core/double-shell structure have demonstrated high chemical and photochemical stability. The AgInS2/GaSx/ZnS NCs were prepared via three steps: (i) synthesis of AgInS2 core NCs by solvothermal method at 200 oC for 30 min, (ii) shelling GaSx on AgInS2 core NCs at 280 oC for 60 min to produce the AgInS2/GaSx core/shell structure, and (iii) the outermost ZnS shelling at 140 °C for 10 min. The synthesized NCs were characterized in detail by using appropriate techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), and optical spectroscopies. The luminescence evolution of the synthesized NCs is as follows: from the broad spectrum (peaking at 756 nm) of the AgInS2 core NCs to become the narrow excitonic emission (at 575 nm) prominent beside the broad one after shelling with GaSx, then only the bright excitonic luminescence (at 575 nm) without broad emission after double-shelling with GaSx/ZnS. The double-shell has made the AgInS2/GaSx/ZnS NCs not only remarkably enhance their luminescence quantum yield (QY) up to ~60% but also maintain the narrow excitonic emission stably for a long-term storage over 12 months. The outermost ZnS shell is believed to play a key role in enhancing QY and protecting AgInS2 and AgInS2/GaSx from certain damage.

Highly efficient narrowed emitting AgInxGa1−xS2/AgGaS2 quantum dots via an HF-assisted one-pot synthesis strategy and their light-emitting diodes

“…20,25 However, the use of metal-dithiocarbamate complexes inevitably generates side-products, 32,33 depositing an amorphous layer on the surface of QDs, 32 forming the adsorption layer that may cause lattice mismatch in the core–shell structure. Furthermore, the current synthesis of Ag–In–S based QDs with narrowband emission typically involves intermediate purification steps to ensure the effective coating of the shell, 18,20,21,25,31,32,34–36 which adds complexity and cost to the synthetic route, particularly for large-scale production. 37 Therefore, the development of a simplified synthetic route for the preparation of AIGS/AGS QDs with narrowband emission is crucial for advancing environmentally friendly QDs of the I–III–VI type and their QLED applications.…”

Investigating the effect of Zn doping and temperature on the photoluminescence behaviour of CuLaSe2 quantum dots

“…CuInSe 2 QDs are widely studied materials but they significantly suffer from defect sizes [15] that restrict their usage in potential applications. By synthesizing Cu-Ga-Se [17], Cu-Fe-Se [18], ZnAIS [13], AIS/ZnS [14] QDs and Cu-Al-Se [19] nanorods as an alternative to Indium-based QDs, it is aimed to expand the usage areas of ternary QDs, especially by increasing the PL Quantum Yield value. Therefore, those materials should either be improved by modifications or replaced with new counterparts.…”