An efficient method for the surface functionalization of luminescent quantum dots with lipoic acid-based ligands
journal contributionposted on 22.09.2017, 09:36 by Marcello La Rosa, Tommaso Avellini, Christophe Lincheneau, Serena Silvi, Iain WrightIain Wright, Edwin C. Constable, Alberto Credi
We describe an operationally advantageous general methodology to efficiently activate lipoic acid-based compounds - a family of popular surface ligands for semiconductor nanocrystals - by the use of a borohydride exchange resin, and the use of the activated species to replace the native surface ligands of quantum dots. The procedure enables the phase transfer of the nanocrystals between polar and aqueous media and, if unsubstituted lipoic acid is used, a facile adjustment of their solubility in a wide range of solvents with varying polarity (from hexane to water). We show that the protocol is applicable to different types of nanocrystals and a variety of lipoic acid-based ligands, and that the resulting quantum dots maintain their optical properties - in particular, an intense luminescence - and long term colloidal stability.
Financial support from the EU (FP7-NMP project Hysens, No. 263091), the Italian Ministry for Education, University and Research (PRIN 2010CX2TLM InfoChem), and the University of Bologna is gratefully acknowledged.