It is a polycrystalline Boron-Doped Diamond (BDD) in the form of a square plate available in two dimensions: 7 mm x 7 mm and 15 mm x 15 mm, with thickness of 0.5 mm. BDD is a semi-metallic material characterized by high conductivity and fast electron transfer. BDD electrodes are recognized as being superior to other electrode materials due to excellent electrochemical properties. Main advantages include: (i) outstanding chemical and dimensional stability, (ii) exceptionally low background current, (iii) an extremely wide potential window for water electrolysis, (iv) a broad electromagnetic transparency window of thin films ranging from the UV-Vis region to the far-infrared region, (v) low magnetic susceptibility compared to other electrode materials, and (vi) excellent biocompatibility (sp³ hybridized structure).

Application note
Properties of BDD are particularly important in electroanalysis for the development of sensors and biosensors. BDD electrodes allow to detect many electroactive molecules in aqueous media that would otherwise be masked by water decomposition reactions at higher potentials. The surface of BDD electrode can be further (photo)functionalized or decorated. In order to enhance the electrochemical response in a presence of organic molecules, the surface of BDD can be also modified with metal nanoparticles (e.g. Au). BDD is also a broadly used electrode material for electrochemical energy storage, electrocatalysis or electrosynthesis.
Please note that two larger surfaces have non-equal properties. This is a consequence of postprocessing of BDD polycrystal. While one surface is just polished the second is first laser cut and then polished. The temperature released during the laser cut affects the level of boron doping and in consequence decrease the conductivity. Chemical etching is recommended before use.