Printable electronic

The LEC structure that involves the addition of ionic dopants and surfactants to the printable inks enables the ability to print a top electrode without restriction by the work function of the metal. Silver, nickel, or carbon particle-based pastes are generally the preferred printable electron injecting electrodes however, the shape and size of the particles combined with the softening properties of the solvent can create electrical shorts throughout the device when printed over a thin polymer layer that is only several hundred nanometers thick. For optimal performance, the commercially available pastes must be optimized for printing onto soluble thin films to make a fully screen-printed polymer EL display. 

As discussed in the introduction requirements for the different applications envisaged for printable electronics are very different and will require substrates with different sets of properties. This is summarized in Fig. 7.13 and for this classification covers simple organic circuitry, e.g. RFID, organic based active matrix backplanes, OLED displays, but also includes the requirements of inorganic TFTs on flexible substrates. 

The most active area of research in printable electronic materials has been the general area of solution-processable (and therefore, potentially printable) semiconductors. In general, the materials development activity in printable semiconductors can be broken down into work on (1) soluble organic semiconductors, (2) soluble organic semiconductor precrusors, and (3) soluble inorganic semiconductor precursors. 

Inkjet printed electronics is very attractive as a means of realizing potentially low cost circuits on flexible substrates. Potential applications range from displays to RFID tags to sensors. Over the last decade, a family of high-quality printable electronic materials has been developed, and processes for realizing printed devices have been demonstrated. 

M. Boehm, et al., Printable Electronics for Polymer RFID Applications ,... 

Another important applieation field for printable electronics are backplanes for active-matrix displays. These baekplanes, which contain up to several millions of transistors, ideally will be fully printed. When flexible plastic substrates are used, the displays can be bendable and rollable while retaining their original performance. The stacked layers of materials are extremely thin, in the order of hundreds of nanometers, and therefore light-weight ideal properties for an E-book reader. 

PEDOT PSS represents one of the most explored conductive polymers and is available for some commercial applications in the fabrication of low-cost, flexible, and printable electronic devices. Although the PEDOTrPSS films are also widely investigated for high electrical conductivities (Liu et al., 2015), they remain obviously lower than their inorganic counterparts (Dobbelin et al., 2007). Even worse, the performances, such as efficiency and lifetime of the electronic devices are deteriorated as PSS is strongly acidic and hygroscopic. Therefore, it is critical to further improve the electrical conductivity and stability of the PEDOT PSS film. 

Recently, solid-state or quasi-solid-state electrolytes have received increasing attention since they can greatly promote the development of ESs for portable electronics, wearable electronics, printable electronics, microelectronics, and especially flexible electronic devices. 

PPE-PPV hybrid, 6-9-6-10, 6-19-6-20 PPy nanocapsules, 8-53, 8-59 PPy nanocomposites, 8-49-8-53 PPy nanofibrils, 8-47-8-48 PPy nanotubes, 8-48-8-49, 16-3, 16-5, 16-7 PPy nanowires, 8-47-8-48 PPy tube, 16-7-16-10 Pressure-area isotherm, 9-30 Printable electronics, 9-39 Printing wiring boards with PEDT, 10-2, 10-13 Processibility, 7-36... 

Kim, D., Moon, J., 2005. Highly conductive ink jet printed films of nanosilver particles for printable electronics. Electtochemical and Solid-State Letters 8 (11), J30—J33. 

Coppjer (Cu) nanoparticies are of great interest in various fields, spjecifically that of printable electronics. Cu interconnects less than 20 xm wide can be made with a high resolution screen printer or a sup>er inkjet printer using an ink which contains dense Cu nanoparticies. Cu nanoparticies have been synthesized by various reduction processes from cuprous (Cu(I)) or cupric (Cu(II)) compounds, including direct electrochemical reduction (Han et al., 2006 L. Huang et al., 2006 Yu et al., 2007), chemical reduction (Lisiecki Pdeni, 1993 Lisiecki et al., 19% H. H. Huang et al., 1997 Qi et al., 1997 Ohde et al., 2001), thermal reduction (Dhas et al.. 

Based on their unique properties, metal oxide nanoparticles are used in a variety of applications. ITO nanoparticles, for example, belong to the class of transparent conducting oxides (TCO) and show promise in the field of printable electronics for cheap and reliable polymer-based flexible touch-panels as well as displays [1-3]. As another example, Zr02 nanoparticles are highly attractive for ceramics. 

Reindl A (2009) Dispersing and stabilizing semiconducting nanoparticles for application in printable electronics , Doktorarbeit (FAU Erlangen-Nuremberg)... 

To support it, these days, peripheral technology has also prepared. For example, organic electronics using organic semiconductors and conductors and printable electronics associated with high precision attract a great deal of attention for next-generation flexible displays. 

An emerging field of application for nanocomposite-based structures is in flexible electronics. Intuitively, this is not only because the reinforcement and weight reduction properties of nanoparticles can be controllably dispersed as functionalized nano-structures within flexible composites, but also because the commercial viability of advanced printing technologies for enabling printable electronic circuitry. Figure 10.1 provides an overview of the potential applications of nanocomposites in microelectronics. 

T. Toyama, T. Hama, D. Adachi, Y. Nakashizu, H. Okamoto, An electroluminescence device for printable electronics using coprecipitated ZnS Mn nanocrystal ink. Nanotechnology 20 (2009)055203. 

Accordingly, the chemical and physical properties of the particles can be adapted to specific appUcations. Chemical functionalization is applied for instance (i) for the dispersion of particles in different polar or nonpolar matrices, (ii) to enhance charge transfer between particles in applications of printable electronics, (iii) to control the release of components in life sciences or for corrosion protection by design of core-shell systems and capsules, or (iv) to protect particles from oxidation and other chemical influences. 

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