Highly fluorescence PS@CdTe multilayers core-shell microspheres: Synthesis, structure, luminescence

A novel PS@CdTe multilayers fluorescence microsphere was successfully synthesized by the electrostatic layer-by-layer (LBL) self-assembly technique. The structure, the process of self-assembly and the fluorescence performance were confirmed by high-resolution transmission electron microscope (HRTEM), Zeta potentiometric analyzer and fluorescence spectrophotometer, respectively. The results manifest that when the pH of buffer solution is 7.8, the negative charge on the surface of CdTe quantum dots (QDs) is the largest, which is beneficial to the synthesis of electrostatic self-assembled microspheres. The fluorescence properties of PS@CdTe microspheres increased gradually with the number of layers coated increased, and the optimum number of coating layers is three. Under this condition, the PS@CdTe microspheres exhibited a great increase of 25-fold in fluorescence performance compared to the equal quantity of pure CdTe QDs. Moreover, the emission spectra of PS@CdTe microspheres recorded under the excitation of 410 nm, and shows a strong emission peak located at 524 nm. This kind of core-shell microspheres has a great potential to be used in the field of optoelectronics .