The use of heat transfer fluids in the synthesis of high-quality CdSe quantum dots,core/shell quantum dots, and quantum rods

Abstract

Fluorescent semiconductor nanoparticles, or quantum dots, have potential uses as anoptical material, in which the optoelectronic properties can be tuned precisely by particlesize. Advances in chemical synthesis have led to improvements in size and shape control,cost, and safety. A limiting step in large-scale production is identified to be the rawmaterials cost, in which a common synthesis solvent, octadecene, accounts for most of thematerials cost for a batch of CdSe quantum dots. Thus, less expensive solvents are needed.In this paper, we identify heat transfer fluids, a class of organic liquids commonlyused in chemical process industries to transport heat between unit operations, asalternative solvents for quantum dot synthesis. We specifically show that two heattransfer fluids can be used successfully in the synthesis of CdSe quantum dotswith uniform particle sizes. We show that the synthesis chemistry for CdSe/CdScore/shell quantum dots and CdSe quantum rods can also be performed in heattransfer fluids. With the aid of a population balance model, we interpret theeffect of different HT fluids on QD growth kinetics in terms of solvent effects, i.e.,solvent viscosity, CdSe bulk solubility in the solvent, and surface free energy.