Quenching of quantum dots luminescence under light irradiation and its influence on the biological application

Applications of quantum dots (QDs) can be limited by their stability under intensive irradiation. We have studied the stability of core/shell QD photoluminescence under the irradiation typical for the laboratory or industrial environment. Our results show that QD photoluminescence stability is determined by the structure and thickness of their shell; the latter factor has the strongest effect on the QD resistance to irradiation. It has been shown that the observed photodegradation of QDs is basically caused by the transfer of excited charge carriers outside the QD. An increase in the carrier tunneling length has been shown to be an efficient way to prevent quenching of QD photoluminescence. Storage of chloroform QDs solution under the light should be avoided due to the decrease of the biological applicability.