Solvothermal-Electrosynthesis Diamond-Like Materials

Diamond-like carbon (DLC) containing a significant fraction of sp3 bonds is a metastable form of amorphous carbon. It has high hardness, chemical inertness, optical transparency, and it is a wide band gap semiconductor. DLC has widespread applications, especially as field emission cathode materials for vacuum microelectronic devices, therefore synthesis of DLC has been being a hot research topic. This paper first reviewed the progress in the synthesis of diamond and diamond-like carbon with emphasis on electrodeposition from organic liquids.In this thesis, CHCl3 was chosen as carbon source, using a three-electrode cell,. The ionic liquid ([BMIM]BF4)-CHCl3 electrolyte system was firstly researched, which was heated to reduce the viscosity of ionic liquid and improve the conductivity of system. Raman spectra suggested that the products synthesized at low-voltage were diamond-like material. Compared with the result at room temperature, heating was benefical to form DLC. Propylene carbonate (PC) and tetrabutylammonium chloride (TBAC) were used as solvent and supporting electrolyte. The current efficiency was improved and the reaction time was reduced by heating or passing into argon, but there were not benifit to produce DLC. It may be due to destory the stability of the system resulting less carbon free radicals gathered at the electrode.Using solvothermal-electrochemical method, PC-TBAC-CHCl3 still used as the electrolyte system. The effects of temperature, carbon content and material of the electrode on the production were researched. The optimal conditions were producted which were 100℃, VPC/VCHCl3=3/1 and Pt electrode. The content of sp3-C was 36.2% in the production.As CHCl3 contains hydrogen and C-H bond energy is high, it is difficult to remove hydrogen. CCl4 was chosen as carbon source and the [BMIM]BF4-CCl4 system and PC-TBAC-CCl4 system were respectively researched. Results suggested that the film deposited from CHCl3 containing more sp3-C than from CCl4, which may be due to CCl4 was non-polar, poor electrical conductivity, and poor solubility.