2-mercaptoethanol and dihydrolipoic acid biligand-coated alloyed quantum dots

Abstract

Alloyed quantum dots (QDs) are luminescent semiconductor nanocrystals, which are promising materials in various fields of science and technology, including in bioanalysis. The key requirement for alloyed QDs in polar solutions analysis is hydrophilicity. The modification with dihydrolipoic acid (DHLA) makes it possible to increase the alloyed QDs colloidal stability in a polar medium while retaining the advantages of nanoparticles of this structure, and also allows further electrostatic self-assembly of alloyed QDs with antibodies. The article describes the DHLA-modification of the alloyed QDs composition CdxZn1-xSeyS1-y / ZnS using 2-mercaptoethanol (BME) as an additional hydrophilizing agent. The effect of hydrophilization conditions on the following modified properties alloyed QDs was studied: photoluminescence quantum yield (PLQY), width peak at half maximum (FWHM), luminescence peak position, colloidal stability during long-term storage. The search for the optimal ratio of hydrophilizing agents DHLA:BME was carried out, at which the advantages of the biligand shell would be maximally realized. The methods presented in this work make it possible to obtain alloyed QDs with a high PLQY (about 65%) and a long stability period (more than 3 months).