Cu2+ and Fe2+ Sensor Based on CdTe QD@ZIF-8 Composites

TGA capped CdTe QDs have been encapsulated in miroporous ZIF-8, with no obvious deterioration of their photoluminescence property. The resulted CdTe QD@ZIF-8 composites show a higher luminescent stability in various buffer solution. The material has successfully been used as a luminescent indicator for the detection of Cu(2+) and Fe(2+) ions. The luminescence of CdTe QD@ZIF-8 composite quenches only in the presence of Cu(2+) or Fe(2+) ions. The linear ranges of detection have been estimated as 1~50 uM for Cu(2+) ions and 1~60 uM for Fe(2+) ions, respectively. A "competing transmission" mechanism has been proposed to explain the selectivity of the sensor to detecting Cu(2+) and Fe(2+) ions. Luminescent quenching can only occurred when the bonding power of QD surface surpasses the adsorptivity of the outside ZIF-8 to the metal ions.