Green-Emissive Copper Nanocluster with Aggregation-Enhanced Emission for Selective Detection of Al3.

Selective detection of Al3+ is of great significance both for the benefit of human health and environmental safety considerations. In this work, a sensitive and selective fluorescence assay for Al3+ was proposed based on the green-emissive Cu nanoclusters (Cu NCs). Different from the commonly reported works, the green emissive Cu NCs showed dual emission bands at 450 and 510 nm, attributed to the reaction product between polyvinyl pyrrolidone and ascorbic acid and the Cu core, respectively. Al3+ could induce the aggregation of Cu NCs by forming covalent bonds, which results in the enhancement of photoluminescence intensity. This enhancement phenomenon is rather selective to Al3+ , which endows the detection in real samples. These results provide new insights for the fluorescence mechanisms of metal NCs, which also provided a functional luminescent material for various applications, such as chemical sensing, bioimaging and photoelectric devices.

Fabrication of Highly Luminescent and Thermally Stable Phosphors through In-Situ Formation of BaSO4 on Sulfur Nanodots.

Producing high performance phosphors using abundant and non-toxic precursors yet straightforward methods are promising but still a challenging task. Herein, highly luminescent and thermally stable phosphors were fabricated through an in situ precipitation synthesis strategy. Sulfur nanodots (S-dots) act as the precursors for precipitation reactions and also provide the luminescent centers. Structural and optical characterization investigations suggest that S-dots are incorporated in the matrix of BaSO4 , and BaSO4 provides passivation effect for the surface ligands or traps of S-dots. This results in the promotion of photoluminescence quantum yield from 23 % to 58 %, and the BaSO4 matrix also leads to the obvious promotion of thermal stability. These merits endow the construction of phosphor-based light-emitting diodes by utilizing the S-dots@BaSO4 hybrid phosphors as a color conversion layer. These research results are significant for developing sulfur-based luminescent materials, and also provide a solid and universal theory to produce high quality phosphors.

Photoluminescence investigations of sulfur quantum dots synthesized by a bubbling-assisted strategy.

Sulfur quantum dots (S-dots) emerge as promising luminescent materials owing to their remarkable optical properties. However, the mechanisms of their formation and photoluminescence remain concealed. We reveal these mechanisms by the bubbling-assisted synthesis and spectroscopic study of S-dots formed from sulfur ions produced by the alkaline oxidation of bulk sulfur under the passivation of PEG. The emission colour of the S-dots depends on the size, explained by the quantum confinement effect. The dots' luminescent quantum efficiency is strongly affected by the surface sulfur species, which is optimized by the proper surface oxidation. The simple synthesis, excellent luminescence properties, and metal-free nature attract S-dots to optoelectronic and electroluminescence applications.