Dual Functional Hydrogen Peroxide Boosted One Step Solvothermal Synthesis of Highly Uniform Sulfur Quantum Dots at Elevated Temperature and Their Fluorescent Sensing

[Display omitted] •Ultra-small uniform sized SQDs with quantum yield up to 10.3% was prepared in the presence of H2O2 as a dual functional reagent.•The SQDs exhibit a time dependent size distribution possibly arises from the etching-assemble-etching process.•The emissive SQDs displays a rich surface and were employed for the Fe3+ as well as cellular imaging. The dual functional hydrogen peroxide (H2O2) assisted strategy for preparation of homogeneously distributed sulfur quantum dots (SQDs) with tunable size and prominent photoluminescence (PL) property is originally proposed via a one-pot solvothermal method. The synthesis of SQDs was demonstrated by treating sublimated sulfur powder and polyethylene glycol-400 (PEG-400) in the presence of H2O2 at elevated temperature. The H2O2 acts as a dual-functional reagent which could suspend the sulfur powder and etching bulk sulfur to construct uniform SQDs. At elevated temperature, the sulfur powder are easily transformed to molten sulfur which simultaneously acts as solvent. The as obtained SQDs exhibit a uniform size distribution, excellent PL properties with quantum yields (QYs) up to 10.3 %, superior dispersibility, and eminent photo stability. Moreover, morphology and element characterization reveal that the surface of spherical SQDs equipped with abundant oxidized sulphur species, while the diversification in the PL and QYs of SQDs under different reaction time are derived from the difference in their particle size which is proposed by the etching-assemble-etching process. Finally, the resultant SQDs was utilized as a sensitive iron ions (Fe3+) sensor with limit of detection (LOD) up to 10.80 nM as well as their investigation for fluorescent cellular imaging.