Electrogenerated chemiluminescence at boron-doped diamond electrodes

Electrogenerated chemiluminescence (ECL) refers to the phenomenon of light emission from molecular species which is triggered by an electrochemical reaction. Therefore, like most electrochemical systems, the electrode material plays a pivotal role and much effort has been made in order to find the best material for ECL, in terms of light signal intensity and long-term stability, especially after the development of ECL for analytical applications. In this article, we will introduce and highlight the distinctive features of boron-doped diamond (BDD) as an electrode material for ECL which has complementary properties compared to the most common metals (e.g., Au or Pt) and carbon materials (e.g., glassy carbon, carbon nanotubes and graphene). Boron-doped diamond electrodes emerged as novel electrodes, gaining more and more interest from the electrochemical community for their peculiar characteristics such as a wide solvent window, low capacitance, resistance to fouling and mechanical robustness. Furthermore, compared to metal electrodes, BDD does not form an oxide layer in aqueous solutions, and the sp(3) carbon hybridization gives BDD the ability to enable peculiar electrochemical reactions that are not possible on sp(2) carbon materials. Electrogenerated chemiluminescence investigations with boron-doped diamond electrodes have been reported for common ECL systems (luminophores and co-reactants), and special ECL that is only possible on BDD which includes the in situ electrochemical generation of the co-reactant.