Au nanospheres modified boron-doped diamond microelectrode grown via hydrogen plasma etching solid doping source for dopamine detection

Boron doped diamond (BDD) electrode is a promising electrochemical material for detecting dopamine level in the human's body. In this work, we developed a new doping source - graphite and solid boron oxide powders to synthesize BDD film with microwave plasma chemical vapor deposition, so as to avoid using toxic or corrosive dopants, such as boroethane and trimethylborate. The synthesized BDD film is pinhole free and with high doping density of 8.44 × 10²⁰ cm⁻³ calculated from the Raman spectroscopy. Subsequently, Au nanospheres were decorated on the surface of BDD film to improve electrochemical performance of the BDD film. The Au nanoparticles modified BDD electrode demonstrates an excellent electrochemical response, a high sensitivity (in the range of 5 μM-1 mM), and a low detection limit (∼ 0.8 μM) for detecting dopamine.