Facile synthesis and step by step enhancement of blue photoluminescence from Ag-doped ZnS quantum dots

Abstract

Our results pertaining to the step by step enhancement of photoluminescence (PL) intensity from ZnS:Ag,Al quantum dots (QDs) are presented. Initially, these QDs were synthesized using a simple co-precipitation technique involving a surfactant, polyvinylpyrrolidone (PVP), in deionised water. It was observed that the blue PL originated from ZnS:Ag,Al QDs was considerably weak and not suitable for any practical display application. Upon UV (365 nm) photolysis, the PL intensity augmented to ~170% and attained a saturation value after ~100 minutes of exposure. This is attributed to the photo-corrosion mechanism exerted by high-flux UV light on ZnS:Ag,AlQDs. Auxiliary enhancement of PL intensity to 250% has been evidenced by subjecting the QDs to high temperatures (200 o C) and pressures (~120 bars) in a sulphur-rich atmosphere, which is due to the improvement in crystallanity of ZnS QDs. The origin of the bright blue PL has been discussed. The results were supported by x-ray phase analysis, high-resolution electron microscopy and compositional evaluation.

Tuning the Optical Band Gap of Semiconductor Nanocomposites—A Case Study with ZnS/Carbon

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Facile Synthesis of Cadmium-Free Zn-In-S:Ag/ZnS Nanocrystals for Bio-Imaging

“… 12 17 18 19 20 21 22 23 . However, the emission wavelength of these d-NCs shows poor tunability 12 22 24 . Moreover, the complex synthesis process and expensive phosphine precursor are needed upon preparation of InP based NCs 18 25 26 .…”

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