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 × 10 20  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.