Cation Exchange Synthesis of Aliovalent Doped InP QDs and Their ZnSexS1-x Shell Coating for Enhanced Fluorescence Properties.

Abstract

III-V quantum dots (QDs), in particular InP QDs, have emerged as high-performance and environmentally friendly candidates to replace cadmium based QDs. InP QDs exhibit properties of direct band gap structure, low toxicity, and high mobility, which make them suitable for high-performance optoelectronic applications. However, it is still challenging to precisely regulate the components and crystal structure of InP QDs, especially in the engineered stable aliovalent doping. In this work, we developed our original reverse cation exchange strategy to achieve Cu+ doped InP (InP:Cu) QDs at lower temperature. A ZnSexS1-x shell was then homogeneously grown on the InP:Cu QDs as the passivation shell. The as-prepared InP:Cu@ZnSexS1-x core-shell QDs exhibited better fluorescence properties with a photoluminescence quantum yield (PLQY) of 56.47%. Due to the existence of multiple luminous centers in the QDs, variable temperature-dependent fluorescence characteristics have been studied. The high photoluminescence characteristics in the near-infrared region indicate their potential applications in optoelectronic devices and biological fields.