Special Morphology Of Boron-doped Diamond Films And Applied Research

Boron-doped diamond (BDD) is an alternative to traditional carbon electrodes that provides superior chemical stability, low background currents, good compatibility, and a wide potential window of water stability. Until now, planar BDD films have been the most studied form of diamond electrodes. To improve the electrochemical performance of electrodes many efforts have been made. These include modification of mediators on electrode surfaces and changing surface morphologies of diamond electrodes. To obtain special micro- or nano- structured diamond films, expensive devices and elaborate techniques are always needed. Therefore, it will be of great significance to obtain better electrochemical properties by only changing the surface morphologies or areas of diamond electrodes. In this paper we have carried out researches on the construction of some special diamond films and their electrochemical biosensing of bio-related materials. A hot filament chemical vapor deposition (HFCVD) device was taken for the preparation. In addition, an immunosensor based on BDD films for detection of gatifloxacin was also investigated. These works are listed as follows:1. Firstly, silicon nanowires (SiNWs) were prepared by EMD (electroless metal deposition) method. Secondly, vertically aligned boron-doped diamond nanorod arrays (BDDNA) were successfully fabricated by depositing a diamond film onto the SiNWs using HFCVD technology. The electrochemical behaviour of the BDDNA electrode was discussed. The impedance behaviour of the BDDNA electrode was like that of porous electrodes.2. Electrochemical detection of glucose on the BDDNA electrode was carried out. The BDDNA electrode, even without any modification, showed excellent electrochemical activity toward glucose in basic solution with a sensitivity of 8.1μA mM-1 cm-2. Furthermore, electroanalysis of adenine, biapenem and propyl gallate were made on the BDDNA electrode compared with a planar BDD electrode prepared under the same deposition conditions. The detection limit of the BDDNA electrode is wider and the sensitivity is better than that of the BDD electrode. 3. By means of delicate and conventional methods based on lithographic process and HFCVD technology, a novel boron-doped diamond micro network (BDDMN) pattern on a SiO2 wafer was successfully fabricated. The electrochemical properties of the BDDMN electrode were studied. And the electroanalysis of dopamine (DA), ascorbic acid (AA), and uric acid (UA) on the BDDMN electrode was investigated. In addition, a primary research on gas sensing on the BDDMN film was also carried out.4. A novel electrochemical immunosensor for rapid determination of trace amount of gatifloxacin was constructed by immobilizing the anti-gatifloxacin antibody on a BDD film electrode. No electro active species was added during the measurement. Impedance and Mott-Schottky measurements were employed to investigate the electrochemical characteristics of the immunosensor during binding procedure of gatifloxacin with the antibody on the surface of the electrode. The advantage lied in the immunosensor based upon the outstanding properties of BDD and the easy-handing procedures.5. Preparation of some special diamond films with different morphologies was made by HFCVD technology. These included network-, ball-, point lattice-, ring-, square-, cake-, stripe-like diamond films, and dispersed boron-doped diamond particles. Our methods were simple, convenient and low-cost.