Carbon nanotube (CNT) forest grown on diamond-like carbon (DLC) thin films significantly improves electrochemical sensitivity and selectivity towards dopamine

In this study we demonstrate a scalable and CMOS compatible synthesis of robust diamond-like carbon (DLC)–multi-walled carbon nanotube (MWCNT) hybrid electrodes. MWCNTs were grown directly on top of DLC thin film electrodes by utilizing Al/Co/Fe tri-layer catalyst structure at 550 °C. The structure of the hybrid material was characterized in detail by utilizing scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman investigations and X-ray photoelectron spectroscopy (XPS). After a very simple activation step with nitric acid the material was shown to exhibit a wide stable water window, almost reversible electron transfer kinetics and high sensitivity as well as selectivity towards dopamine (DA) in the presence of ascorbic acid (AA). Thus, it can be argued that the electrochemical properties of DLC and MWCNT were combined in a unique way in this new hybrid nanomaterial. The possible reasons behind the observed behavior are discussed in considerable detail. Despite the fact that present results are valid only for this particular hybrid material synthesized under conditions described in this paper, we anticipate that by utilizing the concept of DLC–MWCNT hybrids, several other novel carbon based electrode materials may be introduced for a wide variety of electrochemical and other applications.