Synthesis of Luminescent CdTe Nanorods on Anodized Aluminum Oxide Template and Their Utility in Divalent Heavy Metal Ion Sensing

A simple one-pot hydrothermal method to grow luminescent CdTe nanorods on porous anodized aluminum oxide (AAO) template is described. These CdTe nanorods on the AAO template were further applied as an optical probe to detect divalent heavy metal ions such as Hg, Pb, Mg and Zn, by examining its photoluminescence (PL) responses. The presence of Pb and Hg ions quenched the photoluminescence (PL) of the CdTe nanorods where as Zn and Mg ions enhanced it with the effect of red shift in the peak position respectively. These PL enhancements/quenching of the nanorods after exposing to the divalent ions were explained on the basis of the active surface related recombination, which depends on the direction of carrier transfer mechanism i.e. from nanorods to the surface adsorbed metal ions or vice-versa and is attributed to the alignment of bands thus formed. The luminescent CdTe nanorods grown on AAO template was found to be effective in sensing metal ions (Pb, Hg, Zn and Mg) up to a micro-molar concentration.