ИСТИНА

Quantum dots (QDs) – nano-sized particles, based on semiconductors, which sizes are less than double Bohr radius. This limit leads to quantum-size effects: optical properties of QDs directly depend on QD’s sizes and magnitude of band gap (Eg). Among the QDs based on III–V materials InP colloidal QDs have gained the attention due to their stability, low toxicity and the intensive luminescence in the visible and near-IR spectral regions. Recently developed approach to producing InP-based QDs by using phosphine (PH3) as a source of phosphorus and indium carboxilates as a source of indium with various carbonic acids as surfactants in nonpolar solvents is the simplest nowadays and leads to relatively narrow particle size distributions, high crystallinity of the nanoparticles and the temporal stability of the optical properties. Nanoparticles doping results in changing of their optical properties. The aim of this work was doping of InP QDs with silver and its effect on nanoparticles optical properties. It was established, that silver dopes InP QDs and gives new energy levels in the band gap that are responsible for near-IR luminescence at approx. 800 nm. Inverse relationship between the magnitude of exitonic peak intensity and quantity of introduced admixture is identified. Increasing quantity of introduced silver relative to the basic component (In) up to 5% leads to exitonic luminescence extinction, while further increasing of this magnitude up to 20% results in complete extinction of luminescence in visible and IR-area. In the case of sample, doped with 0,5% of silver, it was established, that each subsequent fraction of InP QDs contains smaller particles, while real quantity of silver is decreasing. That fact may be explained by competition of bigger radical of oleic acid and silver for the potential location on the surface of nanocrystal. TEM images of samples with various silver concentration showed, that the more silver is introduced in the synthetic mixture the less is the size of nanoparticles. It may be accounted of presence of more centers of crystallization in the samples with large quantity of silver. This work was supported by Russian Foundation for Basic Research Grant No. 16-33-00074 mol-a.