Highly Photo-Stable Type-I PbSe/SnSe and PbSe/SnS Colloidal Core/Shell Quantum Dots

摘要

In an effort to improve photo-stability of IV-VI PbSe and PbS quantum dots (QDs) for application of near infrared-based devices, we have synthesized type I core/shell colloidal QDs with PbSe as the cores, and SnSe and SnS as the shells. The new QDs were characterized by photoluminescence, HR-TEM, XRD and EDX analysis. The improved photo-stability was demonstrated both in solution and solid state, and by photo-bleaching tests upon irradiation with a 450 W Xenon lamp. Absolute quantum yields and fluorescence time-life of the core and type I core/shell QDs were also measured. The decreased quantum yields and fluorescent life-time of the core/shells compared with the cores were observed, which was ascribed to the formation of SnO{sub}2 in core/shell structures. These new type I core/shells will provide new opportunities for IV-VI PbSe and PbS QDs in the application of infrared devices.