Changes in the Optical Properties of CdSTe QDs in Artificial Seawater and Accumulation in Artemia salina.

The key to the success of quantum dots (QDs) within industrial applications is their optical properties. The broad applications of QDs emission wavelengths based on the crystal size can change when they are exposed to different environments like seawater. CdSTe QDs were synthesized in a microwave system at 60, 120, 150, and 180 °C producing different crystal sizes that fluoresce blue (510nm), green (538nm), yellow (566 nm), and red (636nm), respectively. A redshift of the fluorescence indicating possible agglomeration or increase in the crystal size was observed in artificial seawater (40 g/L). Also, a broadening of the emission peaks for the smallest crystals was observed when the CdSTe QDs were in contact with artificial seawater for 72 hours. When A. salina was exposed to CdSTe QDs in artificial seawater, an ingest without loss of fluorescence was observed using fluorescence microscopy. The highest cadmium accumulation (2.2 mg/Kg) into A. salina was observed with the largest crystal synthesized at 180° C, indicating an effect of the crystal size. The small changes and not quenching of the fluorescence in artificial seawater help to understand the behavior of QDs in extreme environments and their applications for photocatalysis in salty environments.