In this contribution, we report an efficient synthesis of Cd-free Ag−In−S /ZnS (AIS/ZnS) quantum dots (QDs) using low toxic precursors and investigation of their optical properties. The nanocrystals (NCs) have been successfully obtained directly in aqueous media in the presence of thioglycolic acid (TGA) as stabilizing and reactivity-controlling agent. The coating with ZnS shell leads to the photoluminescence (PL) emission peak blue-shift and the emission intensity enhancement. In order to increase the quantum yield (QY) the nanocrystals were transferred to the organic phase; an influence by post-synthesis treatments of heating was investigated.
Phantoms are an imitation of biological tissue, which are physically modeling the propagation of light in biological tissues. They are required for different purposes, and also repeatability of results is achieved with it. So the fabrication of solid tissue phantoms containing high absorb or luminescence nanoparticles is actual problems for experimenters. The work describes fabrication processing and characteristics of solid tissue phantoms.
We report an efficient synthesis Cd-free CuInS<sub>2</sub>/ZnS (CIS/ZnS) quantum dots (QDs) using low toxic precursors and investigation of their optical properties. The nanocrystals have been obtained via reaction between the acetate salts of the corresponding metals and elemental sulfur in the presence of dodecanethiol in octadecene media at 220°C. Influence of various experimental variables, including temperature, time, ratio of Cu and In precursors were investigated. Thus, it was shown that the photoluminescence (PL) emission wavelength can be tuned by conveniently changing the stoichiometric ratio of the components. The plain CIS nanocrystals did show PL emission but with quite low PL quantum yield (QY). In order to increase the QY of QD luminescence by compensation of the surface defects of QDs cores, the process of covering with ZnS shells was done. During shelling process, increasing of QY and blue shift of emission maximum were detected.
Control methods of temperature fields inside a tissue during laser photothermolysis are an important point to develop biomedical applications of thermal destructions of cancer. One of the most promising approaches to measure and to control of temperature is the application of luminescence nanothermometers such as CuInS<sub>2</sub> nanoparticles. Temperature measurement can be carried out by determination of the maximum of the luminescence band. Thus, we have investigated the influence of exposure time and temperature on the position of the maximum of the luminescence band of CuInS<sub>2</sub> nanoparticles.