# Nanofabrication Techniques in Large-Area Molecular Electronic Devices
## 2 Fabrication of Molecular Films, Deposition Techniques
### The Electrografiting Technique
In addition to the fabrication of exceptionally robust monolayers for molecular electronics applications, this technique is an affordable methodology to reach specific improvements in surface  
Figure 4: Scheme showing the electrografting process for a diazonium salt. functionalization for an extensive variety of substrates. For example, mixed monolayers made of organophosphate derivatives have been electrografted onto nitinol (NiTi), which is an alloy often employed in the biomedical field, in order to prevent the release of the possibly carcinogenic Ni\({}^{2+}\) ions [327]. [PERSON] et al. [143] modified a GLAD-ITO substrate by the electrografting of a porphyrin diazonium salt, showing the possibility to introduce molecular functionalities, such as photo-activity on nanostructured metal oxides electrodes. Moreover, polymers, such as the PEDOT (Poly(ethylenedioxythiophene) films, have been electrografted to repair IMPC (Ionic exchange polymer metal composite) to overcome the problem of water leakage and also providing reinforced properties to the electrode [328]. Another approach to enhance the adhesion of PEDOT onto ITO and gold surfaces was presented by [PERSON] et al. [329], who introduced a two-step strategy in which the first step consists of the fabrication of an electrografted promoter layer based on EDOT or thiophene moieties. Likewise, materials, such as carbon nanodots (CD) have been immobilized onto carbon substrates, through the attachment of nitrogen moieties at the nanodot surface (diazotized N-CD), resulting in carbon substrates with new performances in sensing applications [330]. Finally, other conductive substrates such as carbon composite electrodes, including thermoplastic electrodes (TPE) [331], edge plane pyrolytic graphite electrodes (PGEs) [332], glassy carbon (GC), and pyrolyzed photoresist (PPF) [333], have also been modified by electrografting. Finally, two useful and recent advances in this field are worth mentioning. One of them results from the merge of the LB and the electrografting techniques and was recently published by [PERSON] et al. [334]. In this methodology, the electrografting process occurs simultaneously to the transference of the Langmuir film onto the solid substrate. The other relevant approach results from the combination of EG with the electrode mediated shadow edge deposition methodology; here, molecules of 9,10-diox-1-anthracenediazonium salt were covalently attached to metallic nanotrenches producing stable and reproducible lateral architectures of molecular junctions [335]. Although EG is widely utilized for the construction of monolayers with applications in molecular electronics, this technique is also used in many other research fields as well as in industrial applications. In this context, it is worth mentioning the development of a diazonium-based biochip for surface plasmon resonance (SPR) analysis, a well-established technique for studying affinity between biomolecules whose interaction takes place in a liquid/solid interface [336], by electrografting of a carboxybenzene diazonium salt [337]. Additionally, electrografting, followed by a post-functionalization, is being an interesting approach in the design of well-defined interfaces for electrochemical (bio) sensing, very important in fields, such as chemistry, materials science, engineering, biology or medicine [320]. Furthermore, EG is an important tool to modify electrodes in bipolar electrochemistry applications, which involves two feeder electrodes and a conducting object (the bipolar electrode) in an electrolytic solution; a field of renewed interest in the last decades, due to its use in materials science or sensing [338]. Accordingly, EG can be applied in a wide range of applications in the areas of catalysis, biosensors, sensors, corrosion protection, composite materials, energy conversion, energy store, or superhydrophobic coatings, which reveals the enormous possibilities of the EG methodology to fabricate bi-dimensional arrangements using a wide range of materials.