Surface modification of semiconductor nanocrystals by a methanofullerene carboxylic acid

We report, for the first time, on successful binding of a fullerene derivative, namely 3,4-dihexyloxyphenyl-C61-butyric-acid (dPCBA) to PbS and CdSe nanocrystals (NCs). This molecule is an excellent candidate to serve as electroactive ligand for NCs and form novel complexes, which could be very promising building blocks for optoelectronic devices. The surface modification phenomenon was followed by steady-state and time-resolved photoluminescence (PL) experiments. The dramatic PL quenching in the case of both NCs indicates photoinduced charge transfer from NCs to dPCBA molecules as a result of effective coordination of dPCBA to the NC surface. The electrically active nature of the new complexes is proven by current–voltage measurements on thin films of the NC-dPCBA complexes.