In an attempt to give a brief introduction to carbon nanotube inkjet printing, this review paper discusses the issues that come along with preparing and printing carbon nanotube ink. Carbon nanotube inkjet printing is relatively new, but it has great potential for broad applications in flexible and printable electronics, transparent electrodes, electronic sensors, and so on due to its low cost and the extraordinary properties of carbon nanotubes. In addition to the formulation of carbon nanotube ink and its printing technologies, recent progress and achievements of carbon nanotube inkjet printing are reviewed in detail with brief discussion on the future outlook of the technology.

It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it is possible to produce devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Existing research has demonstrated that inkjet-printed and paper-based electrochemical sensors are suitable for this application due to advantages provided by the carefully selected materials and fabrication method. Inkjet printing provides a low cost fabrication method with incredible control over the material deposition process, while paper-based substrates enable pump-free microfluidic devices due to their natural wicking ability. Furthermore, electrochemical sensing is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment. By merging each of these favorable techniques and materials and continuing to innovate, the production of low-cost point-of-care sensors is certainly within reach.

This paper presents a fully inkjet-printed electrochemical sensor on paper which consists of carbon nanotube-printed working, reference, and counter electrodes. The proposed technique aims at low-cost and disposable paper-based electrochemical sensors. First, a carbon nanotube (CNT) ink was inkjet-printed directly on paper, forming a conductive network. Additionally, a hydrophobic barrier was patterned on paper to limit the absorption of liquid to the designed area. The inkjet printing method allows for rapid patterning of electrodes on paper, resulting in a simple and effective electrochemical sensor. The sheet resistance of the CNT-printed paper was as low as 1 k / after 33 prints. A potential step voltammetry method was applied to determine the concentration of the analytes, iron ion (Fe 2+ ) and dopamine (DA), with linear ranges of 10 μM-200 μM and 10 μM-100 μM, respectively. The reported approach for a fully inkjet-printed electrochemical sensor is easy and cheap, and it has a potential for simple and rapid paper-based point-of-care diagnostics. Paper-based chemical and biological sensors have become attractive in recent years due to their facile fabrication, simplicity of use, and the ability of paper to easily absorb and retain liquid.1,2 Recent developments incorporate hydrophobic barriers, 3,4 microfluidic channels 5 and stacking layers for sensing purposes. 6 Among other characteristics, paper is a low cost material, readily available, and is also flexible.In order to develop a paper-based sensor, various materials must be patterned on paper for sensing purposes.7 Therefore a quick and easy method to pattern such materials is the subject of great interest. In connection with printed electronics technology, various printing methods exist for patterning conductive materials on thin substrates. 8Among them, inkjet printing has much interest due to many advantages such as automated printing process, mass producibility, and uniform deposition of materials.9 Here, we are interested in utilizing the inkjet printing technology for the development of a paper-based electrochemical sensor.Printing methods have been applied for chemical sensors in a number of ways; however, since further steps were required in order to build a complete device, it is desirable to develop a simpler printing process. For example, inkjet printing was used to print dissolvable materials in order to pattern hydrophobic areas, 10 where it was necessary to dip coat the paper and clean the dissolved material afterwards. In another instance, inkjet printing of metal nanoparticles was performed with an additional sintering step.11 Thus, a simpler one step process to develop a paper-based sensing device is necessary which should be easy and cheap to fabricate.Although paper based analytical devices have been greatly advanced, a simple method of fabrication coupled with reliable detection method is still needed. Our approach targets the fabrication issue by integrating all the fabrication steps into a single method of inkjet printing. This can...

A water-based carbon nanotube ink for inkjet printing was prepared by dispersing single-walled carbon nanotubes (SWCNT) with sodium n-dodecyl sulfate (SDS), an anionic surfactant. A standard Hewlett-Packard (HP) inkjet printer was employed to deposit the carbon nanotube ink onto a transparency film in order to form conductive electrodes. A sheet resistance as low as 132 / was obtained for the carbon nanotube electrodes, which is one of the lowest values ever reported. Using inkjet-printed carbon nanotubes and screen-printed silver epoxy, a cheap, flexible, and disposable electrochemical sensor was fabricated and characterized using cyclic voltammetry (CV). The results of these tests indicate that the fully printed device behaves as a reliable electrochemical ionic sensor. Furthermore, the demonstrations presented in this work show that inkjet-printed carbon nanotube electrodes are very promising and have potential for use in many different applications.

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