Effect of stabilizers on Mn ZnSe quantum dots synthesized by using green method

Abstract

Herein, the effect of three types of capping polymers, mercaptopropionic acid (MPA), polyethylene glycol (PEG), and starch on the photoluminescence of Mn(2+)-doped ZnSe (ZnSe:Mn) nanoparticles, has been investigated. ZnSe:Mn nanoparticles were successfully prepared with a green method of precipitation in aqueous solutions containing MPA, PEG, or starch as stabilizers. The X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy had proved the formation of ZnSe:Mn particles and the interaction between them and the capping agents. The resultant nanoparticles with different capping polymers were identical in optical property; however, photoluminescence quantum yields (PLQY) as well as the photoluminescence lifetime varied by capping agents. Starch-capped ZnSe:Mn nanoparticles had the biggest size compared to others, which was confirmed using transmission electron microscopy, dynamic light scattering, UV-Vis absorbance and Raman spectroscopy. Also, the PL intensity was significantly enhanced with starch-capped ZnSe:Mn nanoparticles. The PLQYs of starch archived 26%, which was 1.23 or 1.8 times lower than that of ZnSe:Mn nanoparticles capping with MPA or PEG, respectively. Furthermore, the highest decline of PL intensity was detected in PEG, which completely diminished in the 19th week, while both MPA and starch endowed ZnSe:Mn nanoparticles with outstanding PL lifetimes diminished over seven weeks.