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 an optical material, in which the optoelectronic properties can be tuned precisely by particle size. 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 raw materials cost, in which a common synthesis solvent, octadecene, accounts for most of the materials 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 commonly used in chemical process industries to transport heat between unit operations, as alternative solvents for quantum dot synthesis. We specifically show that two heat transfer fluids can be used successfully in the synthesis of CdSe quantum dots with uniform particle sizes. We show that the synthesis chemistry for CdSe/CdS core/shell quantum dots and CdSe quantum rods can also be performed in heat transfer fluids. With the aid of a population balance model, we interpret the effect 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.

Preparation of Highly Luminescent Nanocrystals and Their Application to Light‐Emitting Diodes

“…[14] Many researchers make constant efforts to produce high-quality NCs in more reliable, economical, and environmentally friendly synthetic processes. [15][16][17] To obtain the desired optical and electrical properties of NCs, it is important to control the presence of defects on their surfaces. The most well-known method is the preparation of a CdSe/ZnS core/ shell structure by the passivation of the core NC with a wide bandgap material.…”

Synthesis of highly luminescent Cd(Se,S) nanocrystals

“…Cd(Se,S) alloy nanocrystals were synthesized by injection of mixed precursor solution with Se and S into hot Cd precursor solution modified from the synthesis method for spherical CdSe nanocrystals [8,9]. The Cd precursor solution was synthesized by dissolving 8 mmol CdO into the mixture of 10 mmol oleic acid and 20 mL 1-octadecene (ODE).…”

Tailoring the Morphology and the Optical Properties of Semiconductor Nanocrystals by Alloying

“…CdSe nanocrystals were synthesized by injection of selenium precursor solution into hot Cd precursor solution based on the synthesis method for spherical CdSe nanocrystals (Asokan et al, 2005). The Cd precursor solution was synthesized by dissolving 4mmol CdO to the mixture of 10mmol oleic acid and 20ml 1-octadecene (ODE).…”