Diamond‐based Electrodes

Vitale

et al. 2017

Adv Materials Inter

Self Cite

controlled electrical conductivity. The insulating nature of the diamond phase precluded the use of diamond in electro chemistry, and at that time conductivity could be induced in diamond films only by ion implantation. However, as indi cated by the first report [1] the results were not satisfactory because of the structural damages produced by the ions in the dia mond lattice. After the pioneering works by Derjaguin et al., [2] Varnin et al., [3] and Spitsyn et al., [4] the beginning of the "diamond electrochemistry" era started with the settling up and developing of chemical vapor deposition (CVD) metho dologies and the definition of protocols for the growth of the diamond phase under conditions far from the thermo dynamic equilibrium.The feasibility of doping the growing diamond lattice during CVD processes stimulated the development of efficient routes for the realization of highquality, robust, and wearresistant new type of carbon electrodes, to be used for the entire range of the electrochemical applications, from oxidation/reduction reactions, to qualitative and quantitative electroanalysis, to power generation and storage. [5] During the last decades the general trend was to use boron as dopant of diamond. Borondoped diamond (BDD) consti tutes certainly the more common class of conductive diamonds, due to the wellestablished ptype semiconductor behavior and the interesting electrochemical properties of such hybrid system. [6][7][8] However, there are several criticalities related to the use of B to dope CVD diamond layers. First, whereas resistivity of about 10 −3 Ω cm can be achieved with B concentrations up to 10 21 cm −3 , [9] the electrical properties of such structures are dom inated by impurity band conduction with a low mobility that degrades the conducting behavior of the material. [10] Another criticality is related to the high toxicity of boron and to the con sequent limitations in the use of Bdoped electrodes in applica tions requiring biocompatibility.Several other elements such as N, P, Na, Li, Ti, W, and Nd have been proposed as dopants to induce in diamonds a con ductive or semiconductive behavior and to match specific tech nological requirements. [5] A hybrid chemical vapor deposition (CVD)-powder flowing technique specifically developed in lab has been employed to produce high-quality polycrystalline diamond layers containing Ti inclusions. Morphology, structural features, and surface composition of nanocomposite diamond-based samples produced by different growth times have been analyzed by scanning electron microscopy, Raman and Auger spectroscopy, respectively. The CVD methodology adopted for the Ti incorporation in the diamond lattice does not perturb the crystalline quality of the diamond matrix, therefore maintaining the outstanding properties of the C-sp 3 phase. The functional properties of the nanocomposite layers have been tested by nanoindentation and I-V measurements. The electrochemical performance of the diamond/Ti electrodes is evaluated by performing cyclic voltammetry in ...

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confidence: 99%

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confidence: 99%

Exploiting the Properties of Ti‐Doped CVD‐Grown Diamonds for the Assembling of Electrodes

Tamburri

Vitale

et al. 2017

Adv Materials Inter

Self Cite

“…[ 1 ] Although the first attempts to manufacture conductive diamond by ion implantation doping were not very satisfactory due to the degradation of the crystal lattice, with the settling of protocols for the realization of diamond films and layers with controlled electrical conductivity the “diamond electrochemistry” era officially started. [ 2 ] In fact, the possibility to dope diamond lattice directly during the chemical vapor deposition (CVD) synthesis allowed for developing high‐quality, robust, wear‐resistant, diamond‐based electrodes. These systems were characterized by a wide potential window that enabled working at potentials otherwise very difficult to accomplish.…”

Section: Introductionmentioning

confidence: 99%

PANI‐Modified Ti‐Doped CVD Diamond As Promising Conductive Platform to Mimic Bioelectricity Functions

Politi

Battistoni

et al. 2021

Adv Materials Inter

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This study is devoted to synthesizing and modifying conductive Ti‐doped diamond (TiD) biosubstrates with polyaniline (PANI) to provide a soft interface with high ionic conductivity and charge storage capacity for developing advanced scaffolds and implantable electrode materials. The diamond supports are prepared by an ad‐hoc chemical vapor deposition methodology allowing for the synthesis and contemporary doping of diamond lattice. An optimized potentiostatic electropolymerization method assures the growth of a homogenous PANI coating on a diamond surface. Scanning electron microscopy, atomic force microscopy, Raman, and reflectance infrared spectroscopy characterizations guarantee the production of nanostructured diamond layers with high surface electrical conductivity and good phase quality as well as of a rough polymer film in the conductive emeraldine form. Cyclic voltammetry and electrochemical impedance spectroscopy measurements point out a quasi‐reversible electron transfer among polymer chains ruled by the bulky dodecyl sulfate anion chosen as polymer dopant. This induces a cation exchange with the solution upon backbone redox reactions. The capability of the PANI‐TiD system to transduce ionic current into electronic current and vice versa via redox reaction with the surroundings can be reliably exploited to reproduce electrical stimulation processes through which to mimic the original bioelectricity functions of the human body for advanced biomedical applications.

“…[12][13][14] Being characterized by chemical inertness, high biocompatibility and excellent hardness, diamond has the additional advantage of being synthesizable in both electrically insulating and conducting forms. [15,16] This interesting feature is obtained by tailoring the incorporation of foreign species within the diamond lattice, allowing for producing doped-diamond materials functioning as neural interfaces. [17,18] However, to the best of our knowledge, the use of diamond-based systems for assembling devices with resistive switching properties has been limited to a few examples in the literature.…”

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confidence: 99%

A Ti‐Doped Chemical Vapor Deposition Diamond Device as Artificial Synapse for Neuromorphic Applications

Battistoni

Adv Materials Technologies

Tamburri

et al. 2023

Self Cite

The great demand of multifunctional portable electronic products in daily life and the need of a large integration of memories with logic devices and sensors, have increased the interest in the identification of suitable materials for neuromorphic computing applications. Major innovations in this direction have been achieved by exploring materials belonging to different fields of applications and taking advantage of already consolidated deposition methods. Despite the great interest in the field and the large use in complementary applications such as sensing electrodes, neural and cellular interfaces, the use of diamond‐like materials in neuromorphic applications is still limited to a few examples. Herein, the development of a synaptic element based on high‐quality polycrystalline diamond layers containing Ti inclusions showing a marked and reproducible resistance switching behavior is reported. Realized by means of a hybrid chemical vapor deposition‐powder flowing technique, this titanium doped diamond shows a 3D polycrystalline organization that is characterized by globular grains of a few microns. The coupling of Raman spectroscopy, X‐ray photoelectron spectroscopy, and X‐ray diffraction analyses confirms the good quality of diamond phase and convincingly points out the inclusion of the titanium species within the diamond lattice.