Surface processes during purification of InP quantum dots.

Natalia Mordvinova,Sergey Dorofeev,Artem Abakumov,Alexander Vinokurov,Pavel Emelin,Tatiana Kuznetsova

doi:10.3762/bjnano.5.135

Abstract

Recently, a new simple and fast method for the synthesis of InP quantum dots by using phosphine as phosphorous precursor and myristic acid as surface stabilizer was reported. Purification after synthesis is necessary to obtain samples with good optical properties. Two methods of purification were compared and the surface processes which occur during purification were studied. Traditional precipitation with acetone is accompanied by a small increase in photoluminescence. It occurs that during the purification the hydrolysis of the indium precursor takes place, which leads to a better surface passivation. The electrophoretic purification technique does not increase luminescence efficiency but yields very pure quantum dots in only a few minutes. Additionally, the formation of In(OH)3 during the low temperature synthesis was explained. Purification of quantum dots is a very significant part of postsynthetical treatment that determines the properties of the material. But this subject is not sufficiently discussed in the literature. The paper is devoted to the processes that occur at the surface of quantum dots during purification. A new method of purification, electrophoresis, is investigated and described in particular.

Highlights

Colloidal semiconductor nanocrystals (NCs) have been studied extensively for the last two decades due to their unique sizedependent optical properties and their potential applications in the areas of photoluminescent devices, light-emitting diodes, displays, photodetectors, photovoltaic devices, solar cells and biological imaging [1,2]
In our previous paper [5] we described a low-temperature (160–200 °C) synthesis of quantum dots (QDs) that is accompanied by the formation of In(OH)3
Electrophoresis is a fast and efficient technique that enables the purification of QDs from byproducts, including ODE, that contaminate the sample

Summary

Introduction

Colloidal semiconductor nanocrystals (NCs) have been studied extensively for the last two decades due to their unique sizedependent optical properties and their potential applications in the areas of photoluminescent devices, light-emitting diodes, displays, photodetectors, photovoltaic devices, solar cells and biological imaging [1,2]. TEM was performed after the final purification of QDs. The reaction mixture and the last fraction of precipitate with acetone were vacuum-sealed in two ampoules to monitor changes in the intensity of luminescence.

Results

Conclusion