Graphene-amplified electrogenerated chemiluminescence of CdTe quantum dots for H2O2 sensing

Electrogenerated chemiluminescence (ECL) of thiol-capped CdTe quantum dots (QDs) in aqueous solution was greatly enhanced by PDDA-protected graphene (P-GR) film that were used for the sensitive detection of H 2 O 2 . When the potential was cycled between 0 and −2.3 V, two ECL peaks were observed at −1.1 (ECL-1) and −1.4 V (ECL-2) in pH 11.0, 0.1 M phosphate buffer solution (PBS), respectively. The electron-transfer reaction between individual electrochemically-reduced CdTe nanocrystal species and oxidant coreactants (H 2 O 2 or reduced dissolved oxygen) led to the production of ECL-1. While mass nanocrystals packed densely in the film were reduced electrochemically, assembly of reduced nanocrystal species reacted with coreactants to produce an ECL-2 signal. ECL-1 showed higher sensitivity for the detection of H 2 O 2 concentrations than that of ECL-2. Further, P-GR film not only enhanced ECL intensity of CdTe QDs but also decreased its onset potential. Thus, a novel CdTe QDs ECL sensor was developed for sensing H 2 O 2 . Light intensity was linearly proportional to the concentration of H 2 O 2 between 1.0 × 10 −5 and 2.0 x 10 -7 mol L −1 with a detection limit of 9.8 x 10 −8 mol L −1 . The P-GR thin-film modified glassy carbon electrode (GCE) displayed acceptable reproducibility and long-term stability. Copyright © 2012 John Wiley & Sons, Ltd.