Hydrogen Peroxide Assisted Synthesis of Highly Luminescent Sulfur Quantum Dots

Abstract

An H 2 O 2 -assisted top-down approach is used to synthesize brightly luminescent, color-tunable sulfur quantum dots (SQDs), with aphotoluminescence quantum yield of up to 23 %. The formation of SQDs involves dissolution of bulk sulfur powder into small particles in an alkaline environment in the presence of polyethylene glycol, followed by H 2 O 2assisted etching of polysulfide species,which has the advantage of the passivation of surface states.T his synthetic strategy allows us to simultaneously control the final sizeo fS QDs,t o tune their emission color,a nd to improve their emission quantum yield by eliminating surface traps.Down-conversion white light emitting diodes were also fabricated using blue emissive SQDs and orange emissive copper nanoclusters,with CIE color coordinates of (0.33, 0.32) and ah igh color rendering index of 91. The water-soluble,h ighly luminescent SQDs are promising luminescent materials that can be produced from abundant precursor materials.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Oxygen accelerated scalable synthesis of highly fluorescent sulfur quantum dots

“…4c), which is more uniform than previously reported SQDs. 6,8,10 Consistent with the emission and absorption spectra, the reaction time has little inuence on the mean size of SQDs. For example, the average diameter of SQDS with a reaction time of 2 and 10 h is 3.34 nm and 2.76 nm, respectively.…”

“…Recently reported methods for SQDs preparation are seriously limited by the product yield. 5,6,8,12 In comparison, the yield of SQDs prepared under an O 2 atmosphere with a reaction time of 10 h could reach as high as 5.08%, which is more than vefold that of the SQDs prepared under an air atmosphere with a reaction time of even 60 h (0.87%). This indicates that reaction under an O 2 atmosphere could greatly increase the product yield value of SQDs (Fig.…”

“…Very recently, Wang et al reported that the QY of SQDs prepared according to Shen's approach could be greatly enhanced by treating the SQDs with hydrogen peroxide. 8 However, rapid and high yield production of highly uorescent SQDs remains a big challenge. To this end, there is an urgent need of an efficient approach to synthesize uorescent SQDs which simultaneously possess high QY and process yield.…”

Luminescent Sulfur Quantum Dots: Synthesis, Properties and Potential Applications

“…[15][16][17][18][19][20] Sulfur quantum dots (SQDs), as a new class of metal-free elemental QDs, have gain tremendous attention since it was first reported that luminescent SQDs could be directly prepared from elemental sulfur. [21][22][23] The SQDs exhibited favorable optical properties and low toxicity, which enable SQDs to find applications similar to or beyond CQDs and SiQDs. Although the research on SQDs is still in its infancy, SQDs have shown potential applications in the fields of sensing, cell imaging, photocatalysis, and so on.…”

Two‐Step Oxidation Synthesis of Sulfur with a Red Aggregation‐Induced Emission

“…Shen and co‐workers reported that processing the bulk sulfur into nanodots (S‐dots) resulted in a blue shift of the emission peak, with a simultaneous improvement of PL QY to 3.8 % . We have reported H 2 O 2 ‐assited synthesis which helped us to improve the PL QY of blue emissive S‐dots to 23 % . However, all the S‐dots reported so far exhibited PL merely in a blue‐to‐green color region, and failed to realize a longer‐wavelength red emission, which is an obstacle for many applications such as bio‐imaging and light‐emitting diodes (LEDs).…”