Commercial Carbon Ink Research Articles

A fully printed sensor with optical readout for real-time flow monitoring

In recent years, there has been a growing interest in the development of flexible thermal flow sensing devices due to their wide-ranging applications. In this study, we present the fabrication of a screen-printed flow sensor with optical readout on a 125 μm polyethylene terephthalate substrate in a three-layer configuration. The device comprises electrodes made from a commercial silver (Ag) ink, a heating area using a commercial carbon ink, and a thermochromic (TC) layer employing a commercial ink with a standard activation temperature of 31 °C. We designed a specialized experimental setup to evaluate the performance of the optical flow sensor under static and dynamic conditions. To analyze the device’s thermal response and performance across various flow conditions, we utilized a combination of electrical measurements and infrared (IR)-optical imaging techniques. The all-printed device operates on the basis of a thermodynamic cycle frequency, which activates the TC ink, causing it to blink at a frequency related to the flow passing over the sensor. The results of our preliminary testing are highly promising, as the sensor successfully demonstrated a clear relationship between flow and optical duty cycle. This innovative device offers a contactless, low-cost, easy-to-use flow detection method and holds significant potential for various practical applications.

Nanocellulose based carbon ink and its application in electrochromic displays and supercapacitors

Conventional electronics have been highlighted as a very unsustainable technology; hazardous wastes are produced both during their manufacturing but also, due to their limited recyclability, during their end of life cycle (e.g. disposal in landfill). In recent years additive manufacturing processes (i.e. screen printing) have attracted significant interest as a more sustainable approach to electronic manufacturing (printed electronics). Despite the field of printed electronics addressing some of the issues related to the manufacturing of electronics, many components and inks are still considered hazardous to the environment and are difficult to recycle. Here we present the development of a low environmental impact carbon ink based on a non-hazardous solvent and a cellulosic matrix (nanocellulose) and its implementation in electrochromic displays (ECDs) and supercapacitors. As part of the reported work, a different protocol for mixing carbon and cellulose nanofibrils (rotation mixing and high shear force mixing), nanocellulose of different grades and different carbon: nanocellulose ratios were investigated and optimized. The rheology profiles of the different inks showed good shear thinning properties, demonstrating their suitability for screen-printing technology. The printability of the developed inks was excellent and in line with those of reference commercial carbon inks. Despite the lower electrical conductivity (400 S m−1 for the developed carbon ink compared to 1000 S m−1 for the commercial inks), which may be explained by their difference in composition (carbon content, density and carbon derived nature) compared to the commercial carbon, the developed ink functioned adequately as the counter electrode in all screen-printed ECDs and even allowed for improved supercapacitors compared to those utilizing commercial carbon inks. In this sense, the supercapacitors incorporating the developed carbon ink in the current collector layer had an average capacitance = 97.4 mF cm−2 compared to the commercial carbon ink average capacitance = 61.6 mF cm−2. The ink development reported herein provides a step towards more sustainable printed green electronics.

Agricultural waste-derived moisture-absorber for all-weather atmospheric water collection and electricity generation

Abstract Harvesting water and energy from ambient environment promises to relieve the worldwide fresh-water scarcity and energy shortage. The fabrication of well-designed materials for atmospheric water harvesting (AWH) requires highly-technical skills, hampering practical applications in isolated regions or after natural disasters. Herein, we report an efficient moisture absorber from waste corn stalk for AWH and for concurrent electricity generation. The sample can adsorb water at capacities of 0.46–1.84 kg kg−1 under relative humidity of 20%–80%. Moreover, with surface modification using commercial carbon ink, a corn stalk slice (3 cm × 1 cm × 0.2 cm) can output a stable open-circuit voltage of ~0.6 V in the air. Density functional theory calculations reveal that the oxygen groups in the carbon ink contribute to the power generation in the corn stalk. When connected in series, corn stalk slices can directly power an electronic calculator. This study contributes to the development of practical strategies to address issues in the water-waste-energy nexus.

Nano Structured and Pyrolytic Deposited Carbon Electrodes for Detection of Nitroaromates – a Comparison

IntroductionNitroaromatics like 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT) are long-lasting organic pollutants in natural water and soil caused mainly by the military usage. Nano structured electrodes are established in detection of such compounds in water by linear sweep voltammetry (DP) [1]. On the other hand, it could be shown that screen printed carbon electrodes [2] and such made of pyrolytic deposited carbon are also suited for that purpose [3]. Both kind of electrodes were investigated regarding the determination of nitroaromatic compounds in aqueous solution. The aim of this paper is to compare the performance of both electrodes in comparison to commercial electrodes respecting sensitivity, selectivity and long-term stability.ExperimentalElectrodes using carbon nano-tubes and gold nano-particles on printed carbon are commercially available (DropSens, Spain DRP-110CNT-GNP). Screen printed electrodes (SPCE) of 3mm in diameter were industrially like produced on an alumina substrate with a commercial carbon ink (DuPont) carbon paste. Pyrolytic graphite layer were deposited by high temperature decomposition (1050 °C) of aromatic vapor for 15 min with high reproducibility (PyGE). Solid state analyses as XRD and SEM analysis show crystalline carbon with a sp2 hybridization (Fig. 1). The setup of the electrodes is seen in Fig. 2. All experiments were performed in a three electrode arrangement using platinum counter electrode and Ag/AgCl,Cl--reference electrode in a buffer solution. Voltammetric experiments were performed by a PalmSens potentiostate (Palm Instruments, NL). DRP-110CNT-GNP were investigated by linear sweep voltammetrie. SPCE and PyGE were measured in differential pulse voltammetry mode (DPV). The parameter for the DPV were selected as follows: scan rates of 15 mV∙s-1 to 20 mV∙s-1, amplitude of 50 mV and step height of 5 mVResults and discussionThe potentials of the single reduction peak of nitro-aromates can be clearly separated (Fig. 3) for both kind of electrodes, SPCE and PyGE. The nitroaromates trinitrotoluene (TNT) and dinitrotoluene (DNT) are reduced and dopamine is oxidized in DPV mode (Fig.4). The peak currents are proportional to the TNT concentrations with a sensitivity of 2.7 nA/ppb for SPCE (Fig.5) and 0.78 for PyGE (Fig. 6) at the characteristic peak potential of -0.59 V (R²=0.99). Commercial electrodes DRP-110CNT-GNP made of carbon with gold nano particles require a special treatment in cyclo-voltammertic mode up to stable measuring conditions. The sensitivity of 2.8 nA/ppb is high compared to PyGEs. The relative errors in measuring cycles (35 %) are very much higher than those for PyGEs (5 %). PyGE do not need a special pretreatment before use.Screen printed and pyrolytic deposited carbon electrodes can be applied in air saturated aqueous solutions like in field application. For both electrodes, SCPE and PyGE, the oxygen reduction peak do not interfere with the reduction of the nitro groups. The manufacturing tolerances become smaller in the row DRP-110CNT-GNP, SPCE, PyGE. PyGEs can be produced in few steps with very small deviations. They can stored in air or in water over years without a loss of performance. Commercial electrodes are very complex in setup and obviously not so easy to produce in proper quality. Furthermore, their signals are remarkably influenced by oxygen so that measurements in air are not possible.

Hybrid graphene aerogel intermedium for bendable supercapacitor electrode

Porous structure materials indicate brilliant distribution and great absorption ability, that suggesting the potential application of aerogel state graphene based materials. Aerogel intermedium assisted method was developed and optimised to prepare bendable electrode. Hydrothermal schedule was utilised suggesting potential application at low cost and large-scale factory print issues, rather than consuming high money cost and long labour time. Nickel sulphide has been anchored onto the graphene aerogels via one-pot hydrothermal method. The membrane electrode was made with the carbon ink and aerogel intermedium on the Poly(ethylene terephthalate) (PET) plate. The bendable electrode was fabricated with intermedium and commercial carbon ink, and indicates good performance and economic consumption. The complex membrane capacitor shows the much more brilliant performance than the pure carbon membrane capacitor, with specific capacitance (31.40 mF/cm2 at 4 mV/s and 17.74 mF/cm2 at 2 mA/cm2).

High-efficiency hole-conductor-free rutile TiO2-Nanorod/CH3NH3PbI3 heterojunction solar cells with commercial carbon ink as counter-electrode

This work demonstrates the fabrication of a high-efficiency, hole-conductor-free, solid-state perovskite solar cell with TiO2-nanorod arrays (NRAs) as photoanodes and commercial carbon ink as counter-electrodes. TiO2-NRA films of various thicknesses were deposited on FTO electrodes through hydrothermal method for different reaction durations. The effect of the thickness of TiO2-NRA films on device performance was investigated in detail. The TiO2 NRAs/CH3NH3PbI3/C devices based on 688 nm-thick TiO2-NRA films exhibited the optimal performance and power conversion efficiency (PCE) of as high as 8.56%. This value is comparable with the PCE of the recently reported TiO2 NRA/Perovskite/HTM/Au solar cell.

Homemade 3-carbon electrode system for electrochemical sensing: Application to microRNA detection

The homemade production of carbon screen-printed electrodes (C-SPEs) with a three‑carbon electrode system is reported, along with its application in electrochemical sensing. It is highlighted herein as main novelty that a simple carbon ink may be employed in the preparation of the 3-electrode system, including the pseudo-reference electrode, thereby avoiding the addition of silver or other suitable metal and simplify the construction of such devices, reducing costs and time.Screen-printed technology was employed to produce the 3-electrodes and the corresponding electrical paths. This was achieved by the manual application of a commercial carbon ink into a polyvinyl chloride (PVC) substrate allowing the production of >20 SPEs. The optimization of the SPE assembly was made by univariate mode, until the best electrical features of the electrode-solution interface were achieved. Several electrochemical techniques were used for this purpose, namely cyclic voltammetry (CV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS). Raman Spectroscopy and Thermogravimetric Analysis (TGA) were also used for materials and electrode surface characterization.The usefulness of such devices was tested by modifying the working electrode with a sensing layer for microRNA-107, a potential biomarker in Alzheimer's Disease (AD). For this purpose, the surface was functionalized with carboxylic groups, activated by carbodiimide reaction and bound to a suitable oligonucleotide probe containing the complementary sequence. Finally, the microRNA-107 sequence hybridized with its probe, proving the efficiency of the C-SPEs in electrochemical sensing.Overall, this study brings into light the possibility of preparing simple homemade electrodes with a 3‑carbon electrode system that stands out by the low cost, disposability and versatility of the presented platform, holding a great potential for application in point-of-care devices using electrochemical sensing.

Simple and Inexpensive Electrochemical Platform Based on Novel Homemade Carbon Ink and its Analytical Application for Determination of Nitrite

AbstractIn this work we present the development of a simple handmade approach for the easy fabrication of three‐electrode electrochemical devices based on newly in‐house developed carbon ink composed of graphite powder and polystyrene. Different proportions of graphite/polystyrene were investigated for the optimization of the ink. The counter and reference electrodes were produced using commercial carbon ink and silver glue. Scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry were used to investigate the morphology and the electrochemical properties of the sensor. The results showed that the electroactive area of the optimized working electrode was ca. 2.35 times larger than its geometric area. The RSD values obtained for repeatability and reproducibility were 0.20% and 2.78%, respectively, which suggest no significant variation on the electrodes fabricated. The analytical feasibility of the electrode was tested through its application for the determination of nitrite in drinking water. The quantifications were successfully performed at levels below the maximum contaminant level established for nitrite. A limit of detection of 1.42 × 10−6 mol L−1 and recoveries of ca. 103 % were achieved. The results were validated using ion‐chromatography technique with good agreement. The performance of the unmodified sensor proposed here on nitrite determination was better than some recently reported modified electrodes obtained through complex procedures.

Highly-flexible, low-cost, all stainless steel mesh-based dye-sensitized solar cells.

Highly-flexible, ITO-free dye-sensitized solar cells (DSSCs) are fabricated in a simple, all-solution-based, facile, and controllable way. A double mesh structure is applied to DSSCs, and the design principles, especially scale parameters, are analyzed delicately to ensure the power conversion efficiency and mechanical flexibility of the device. The good flexibility of mesh-based DSSCs is verified by systematic bending tests compared to conventional flexible DSSCs based on PET/ITO or metal foil substrates. Commercial carbon ink is used as a counter electrode material, and it is proved to be low-cost and efficient. The double mesh structure design provides an attractive strategy toward the development of flexible and wearable electrochemical energy supplies.

A disposable single-use electrochemical sensor for the detection of uric acid in human whole blood

We report here a non-enzymatic detecting electrode strip for fast monitoring of uric acid in human whole blood. A single-use amperometric uric acid sensor strip, incorporating a three-electrode configuration, has been fabricated on a polypropylene substrate using low cost screen-printing (thick-film) technology. Both the working and counter electrodes were prepared by screen-printing commercial carbon ink. The integration on the same support of pseudo-reference electrode was obtained by screen-printing a commercial silver ink and subsequent electrochemical pretreatment. Simply by placing a 20 μl human whole blood drop on the strip is enough for uric acid analysis by square-wave voltammetry. Real human whole blood samples were analyzed by this method and compared to the phosphotungstic acid clinical test procedure with satisfactory results.

Screen-printed anodic stripping voltammetric sensor containing HgO for heavy metal analysis

A screen-printed disposable sensor for the anodic stripping voltammetric (ASV) analysis of heavy metals was prepared by integrating a HgO-modified working electrode, Ag/AgCl reference electrode, and carbon counter electrode on a polycarbonate strip. The working electrode was screen-printed with phenol resin-based carbon ink containing fine particles of mercuric oxide as a built-in mercury precursor. The mercuric oxide particles exposed on the surface were reduced to fine mercury droplets by in situ or pre-cathodic conditioning in order to allow them to behave as heavy metal collectors in the anodic stripping analysis. The reference and counter electrodes were also screen-printed using commercial silver paste ink modified with finely ground AgCl powder and commercial carbon ink, respectively. The analytical characteristics of the sensor were evaluated using Pb and Cd as probe metals. Detailed preparation procedures and analytical characteristics of the sensor are described.