46 Biosensors Based on Nanomaterials and Nanodevices
peruorated lauric acid, oleic acid, didodecylamine, trioctyl aluminum, and a mixture of
dodecanethiol and trioctylphosphine. The thiols and oleic acid increase the air stability,
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while other ligands precipitate nanoparticles (peruorated lauric acid and the mixture of
dodecanethiol and trioctylphosphine). Ligand exchange can be accomplished by
• Dissolving the QDs in a solution containing the new ligand
21,55,56
• Using a phase-transfer approach, where water-soluble particles are transferred to
an organic phase (or vice versa) by adding a suitable ligand that acts as a phase-
transfer agent such as mercapto acids that have been used to transfer CdTe QDs
from an organic phase to an aqueous ...