Study on the interaction between 2-mercaptoethanol, dimercaprol and CdSe quantum dots.

The interactions between 2-mercaptoethanol, dimercaprol and CdSe quantum dots (QDs) in organic media have been investigated by spectral methods. The results showed that the fluorescence (FL) emission of CdSe QDs gradually decreased, with a slight red-shift, after adding thiols to CdSe QDs solutions. With the increase of the concentrations of thiols, the resonance light scattering (RLS) signal of CdSe QDs had been strongly enhanced in the wavelength range 300-500 nm, which was confirmed by the formation of larger CdSe QDs particles. The effect of thiols on the FL emission of CdSe QDs could be described by a Stern-Volmer-type equation with the concentration ranges 1.0 x 10(-6)-7.5 x 10(-4) mol/L for 2-mercaptoethanol and 1.0 x 10(-7)-2.5 x 10(-5) mol/L for dimercaprol. The possible mechanism of the interaction was proposed according to the results of UV-vis absorption and micro-Raman spectroscopy. The results indicated that FL quenching was mainly attributable to the exchange of the QDs surface molecules.