Electrochemical and electroluminescent behaviors of single meldola's blue-ruthenium (II) bipyridine composite nanoparticles colliding onto an ultramicroelectrode

Stochastic collision nanoelectrochemistry (SCNEC) of single nanoparticles (NPs) is an emerging electrochemical method with significant potential. Herein, we synthesized a new kind of NPs, named Meldola's Blue-ruthenium (II) bipyridine (MDB-Ru) for the first time with the help of ultrasonic energy, and investigated the properties of the single NPs by SCNEC. The quantitative relationship between the concentration of MDB-Ru NPs and the collision frequency was obtained by optimizing collision experimental conditions. By comparing the theoretical calculation with the experimental value, it is speculated that signal loss may be caused by the aggregation of NPs or the large background currents. Furthermore, the electrochemiluminescence (ECL) performance of MDB-Ru NPs colliding in the presence of different co-reactants (TPrA/DBAE) was thoroughly discussed. The results demonstrated that the MDB-Ru NPs can produce a higher current response, and with respect to TPrA, using DBAE generated a higher ECL intensity (similar to 2 times). Moreover, electrochemical and ECL were employed to simultaneously investigate the collision behavior of MDB-NPs, in which demonstrated a strong correlation between the two techniques. This research has broad implications for studying fundamental aspects of SCNEC in organic dyes and provides a foundation for developing analytical sensor techniques using single entity electrochemistry and ECL.