Direct synthesis of quantum dots with controllable multimodal size distribution

Abstract

An approach to directly prepare quantum dots with a controllable multimodal size distribution in a simple one-pot synthesis is presented. In the case of bimodal size-distributed quantum dots, size group A is first grown in the initial stage, followed by a quenching process that can keep size group A in the chemical potential well (intermediate stable state) throughout the subsequent processes. Next, size group B is selectively grown by a series of injections of monomers in a low concentration conducted successively. Average sizes of size groups A and B can be individually controlled by the growth time in the initial stage and the temperature of successive injections of monomers in the last stage, respectively. This technique is also successfully extended to produce quantum dots with trimodal size distribution. © 2009 American Chemical Society.