Chemiluminescence of Mn-Doped ZnS Nanocrystals Induced by Direct Chemical Oxidation and Ionic Liquid-Sensitized Effect as an Efficient and Green Catalyst

Abstract

A novel chemiluminescence (CL) method was proposed for doping water-soluble Mn in ZnS quantum dots (QDs) as CL emitter. Water-soluble Mn-doped ZnS QDs were synthesized by using L-cysteine as stabilizer in aqueous solution. These nanoparticles were structurally and optically characterized by X-ray powder diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), UV-Vis absorption spectroscopy, and photoluminescence (PL) emission spectroscopy. The CL of ZnS QDs was induced directly by chemical oxidation and its ionic liquid-sensitized effect in aqueous solution was then investigated. It was found that oxidants, especially hydrogen peroxide, could directly oxidize ZnS QDs to produce weak CL emission in basic solutions. In the presence of 1,3-dipropylimidazolium bromide/copper, a drastic light emission enhancement was observed which is related to a strong interaction between Cu 2+ and the imidazolium ring. In these conditions, an efficient CL light was produced at low pH which is suggested to be beneficial to the biological analysis. The CL properties of QDs not only will be helpful to study physical chemistry properties of semiconductor nanocrystals but also they are expected to find use in many fields such as luminescence devices, bioanalysis, and multicolor labeling probes.

Chemiluminescence Character of ZnS Quantum Dots with Bisulphite-Hydrogen Peroxide System in Acidic Medium

“…The oxidant radicals, such as HO • and • SO 4 – , injected holes in the 1sh quantum-confined orbital of ZnS QDs (reaction ). , On the other hand, • SO 3 – and • O 2 – radicals served as electron donors, which can easily inject an electron into the 1se quantum-confined orbital of ZnS QDs (reaction ). ,, …”

“… , On the other hand, • SO 3 – and • O 2 – radicals served as electron donors, which can easily inject an electron into the 1se quantum-confined orbital of ZnS QDs (reaction ). ,, …”

“…In addition, it was also demonstrated that H 2 O 2 directly oxidized ZnS QDs to produce weak CL emission in basic medium. 17 Unlike in the above reports, our enhanced CL system operated in an acidic medium.…”

“…UV−Visible and PL Spectroscopy. The prepared ZnS QDs displayed UV absorption at 290 nm, 16,17,22 and the maximum PL emission is located at 428 nm (Figure 1). The PL intensity increased as the excitation wavelength increased up to 300 nm, and beyond that, it decreased.…”

“…Finally, the improved CL emission arose when ZnS QDs* returned to the ground state. The inspiration of Seyed et al 17 on the CL mechanism of ZnS QDs led to the proposition of the third mechanism. 20 3.8.…”