Influence of boron doped level on the electrochemical behavior of boron doped diamond electrodes and uric acid detection

Abstract The boron doped diamond (BDD) electrodes were effective biosensors for the trace detection of organic pollutants in aqueous solution. BDD electrodes with different boron doped levels will display distinct binding energy and carrier density from the perspective of semiconductor, thus significantly impact the current and oxidation peak potential, and further influence detection performance of hazardous substances. In this study, BDDs with different boron doped levels were prepared by hot filament chemical vapor deposition method, followed by characterization of morphology and electrochemical behavior through various methods. Carrier concentrations, which were highly relevant to the charge transfer in diamond lattice, and flat-band potentials that can reflect the oxidation peak potential, were calculated through Mott-Schottky plots. Uric acid was chosen as typical matter for trace detection. As results, the continuous films without cracks were formed for all BDDs by SEM detection, and the size of diamond grain decreased with the increase of boron doped level. Moreover, the carrier concentration enhanced with the increasing boron doped level, thus resulted in the augment of current density. While the Fermi levels calculated from flat band potentials, decreased with the increase of boron doped level, suggesting the decrease of oxidation peak potential. These were in accordance with the results from cyclic voltammetry. Differential pulse voltammetry proved that BDD with higher boron concentration presented higher sensibility to uric acid, lower detection limit and wider linear range, which can be attributed to stronger current response.