Phosphine-free synthesis of selenide colloidal quantum dots

Metal selenide colloidal quantum dots have promising properties for applications in many fields such as gas sensing, food quality control, car accessories for orientation under low-visibility conditions, Infrared detectors for spectrometers. The wide application of selenide nanoparticles is limited due to a number of reasons. High requirements to the equipment for preparation of these materials in an inert atmosphere as well as poor reproducibility of modern synthetic procedures are some of the major reasons for very limited application of the selenide quantum dots today. Preparation of mercury and lead selenide colloidal nanoparticles by standard phosphine based procedures are especially affected by these problems. In this paper we report the application of selenium precursor prepared by dissolution of elemental selenium by action of sodium borohydride in oleylamine in the synthesis of lead selenide and mercury selenide quantum dots. The optical properties of the obtained quantum dots are investigated. This reagent is more easily prepared and less affected by conditions as a common phosphine based precursors. The impact of the reaction conditions and isolation procedures on the size distribution is reported. The work-up procedures are developed.