Flexible electronics applications

Laskarakis A, Logothetidis S, Kassavetis S et al (2007) Surface modification of poly(ethylene terephthalate) polymeric films for flexible electronics applications. Thin solid films 516 1443-1448... 

Fig. 7.3. Upper processing temperature of film substrates of interest for flexible electronics applications.

Fig. 7.13. Property requirements for different flexible electronics applications.

L. Zhou, a-Si H and Pentacene TFT for Flexible Electronic Applications, in Electrical Engineering Department. University Park, Pennsylvania State University, 2005. 

Mabakal, A. et al., Inorganic oxide core, polymer shell nanocomposite as a high K gate dielectric for flexible electronics applications, J. Am. Chem. Soc. Ill (42), 14655-14662, 2005. 

Technical issues in printed electrodes were briefly reviewed for all-printed TFT applications. Surface morphology and edge waviness of the printed electrode should be well controlled to produce uniform and stable TFT behavior and consistent thin-film device performances. This investigation fabricated solution-process TIPS-pentacene based TFT with the printed silver electrodes. Solution-process materials can be readily combined with a low-cost printing process, which can significantly reduce complexity in the fabrication and manufacturing process. In addition, these types of solution-process TFT can be fabricated at low temperatures and they can be also readily implemented on plastic substrates for flexible electronics applications. 

Typical applications for these high speed IR detectors are characterized by strictly controlled, dark environments where a flash fire could originate. While simple high speed infrared systems have been available for several years, modern sensor and filter developments, coupled with state-of-the-art electronics, have resulted in systems tailored for the munitions industry. These systems are more selective within the electromagnetic spectrum, fast in response, and extremely flexible in application to suppression systems. 

Over the past decade, instrumentation has undergone substantial developments in the areas of optics, electronics and data processing software. These have led to improvements in the reliability, accuracy and ease of use of associated instruments. Particularly, the introduction of fiber optics has allowed a greater degree of flexibility in application areas. These include, for example, measurement of oil droplet dispersion in the ocean, on-line monitoring of... 

DNQ—novolac resist chemistry has proved to have remarkable flexibility and extendibility. First introduced for printing applications, DNQ—novolac resists have been available since the eady 1960s in formulations intended for electronics applications. At present, most semiconductor manufacturing processes employ this resist chemistry. Careful contemporary research and engineering support the continuing refinement of this family of materials. 

Fig. 7.2. Cl ass transition of film substrates of interest for applications in flexible electronics.

The second approach has the advantage that it provides flexibility in the choice of means to perform the printing. Figure 10.14 shows a stamp with this construction, designed for plastic electronics applications [42]. It consists of a thin layer of PDMS on top of a sheet of polyimide. The relatively high in-plane modulus of the poly-imide prevents distortions that can frustrate registration. Its small thickness enables the stamp to be bent in a manner that facilitates printing. 

Because of their toughness, flexibility and remarkable thermal stability, linear all-aromatic polyimides are excellent candidate film and coating materials for advanced electronic circuitry and wire coating applications. In past years, however, the inherent insolubility (1-2) of these polymers has somewhat limited their usefulness for electronic applications. 

Solubility was enhanced by the presence of meta and ortho isomer links in the diamine portion of the molecule. Ttie polymers prepared with 3,3 -ODA and 2,4 -ODA were found to be readily soluble at 30-40% solids at room temperature in amide solvents. These polyimides are also readily soluble in low-boiling chlorinated solvents. They can therefore be spray-coated onto desired substrates in the fully-imidized form and thus eliminate the need for taking the substrate to elevated temperatures. Hiese soluble phenoxy-linked polyimides yield tough, flexible, colorless to pale yellow transparent films from amide or cholorinated solvents. Their potential for use in electronic applications should be excellent. 

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