|  Basic electronic structure is composed of a substrate,  backplane electronics, a front plane, and encapsulation. To make the structure  flexible, all the components must bend up to some degree without losing their  function. Two basic approaches have been adopted to make flexible electronics,  that is; transfer and bonding of completed circuits to a flexible substrate and  fabrication of the circuits directly on the flexible substrate. 
 Fraunhofer FEP has worked on cost-effective system solutions  for flexible electronics- a roll-to-roll process line which enables the  application of organic materials for OLED (organic light-emitting diodes), OPD  (organic photodiodes) or OPV (organic photovoltaic) on flexible substrates in  one complete technology. The process includes the structuring, automatic  inspection of the initial substrates, the vapor deposition of the organics and,  finally, the encapsulation of the coated films or glasses. Organic electronics  certainly require flexible electrical contacts. Therefore, Fraunhofer FEP  implemented an additional printing process of metal contacts for the reliable  contacting of, for example, large-area flexible OLED on metal, polymer and thin  glass substrates. In cooperation with printing paste manufacturers and other  suppliers, e.g. machine manufacturers, adhesive manufacturers, encapsulation  film suppliers, the scientists are now able to develop optimized products for  required process steps under production conditions. Dr. Jacqueline Bruckner,  Project Manager Surface Analysis for the roll-to-roll organic technology, says: "Our customers have different requirements to design and mechanical stability  of devices. With our know-how and our process equipment we provide an unique  development platform for all these demands." For example, there are various  solutions for the device contacting. Currently, several contacting solutions  with flat ribbon cable, like ACF (Anisotropic Conductive Film)-Bonding, ACA  (Anisotropically Conductive Adhesive)-Bonding or ACP (Anisotropic Conductive  Paste)-Bonding are evaluated.
 
 The first flexible  display device based on graphene has been unveiled by scientists in the UK, who  say it is the first step on the road towards next generation gadgets that can  be folded, rolled or crumpled up without cracking the screen. The device is the  result of a collaboration between Plastic Logic, a company that specialises in flexible displays, and  researchers led by Andrea Ferrari at the University of Cambridge. Although others have  successfully used graphene to make screen components before, this  is the first example of a flexible screen that uses graphene-based electronics. What we have done here is to include graphene in the actual backplane pixel technology,says Ferrari. This shows that in principle the properties of graphene - conductivity, flexibility and so on - can be exploited within a real-world  display.' The prototype is an electrophoretic display containing the  kind of electronic ink found in e-readers that works by reflecting - rather  than emitting light. Plastic Logic have been working on making these displays  flexible for some time by replacing the glass with bendy plastic, and using  non-brittle components in the electronic layer. Graphene is an ideal material  for this, as it is more flexible and more conductive than the metals currently  used. The team managed to make the graphene electrode in a way that is  compatible with electronics manufacturing, using solution processing rather  than chemical vapour deposition, which often requires temperatures exceeding  1000°Celcius "All the major companies are trying to make bendable and flexible  gadgets, says Ferrari. "We think that graphene will be a powerful addition to  that, and if we manage to make the process easy, scalable and cheap enough,  then it should be considered very strongly by industry. As current displays  go, the team's prototype is basic, capable of showing images in black and white  at a resolution of 150 pixels per inch - akin to that of a basic e-reader. But  Ferrari's team are working on applying the same technology to make a  graphene-based LCD and OLED displays like those used in smartphones and  tablets, capable of showing full colour images and playing video. Their goal is  to have these ready within the next 12 months.
 
 Researchers from the University of Texas at Austin and  Northwestern University have demonstrated a new method to improve the  reliability and performance of transistors and circuits based on carbon  nanotubes (CNT), a semiconductor material that has long been considered by  scientists as one of the most promising successors to silicon for smaller,  faster and cheaper electronic devices. The result appears in a  paper  published in the journal Applied Physics Letters from AIP Publishing.
 To overcome the drawbacks of single-walled carbon nanotube field-effect  transistors and improve their performance, the researchers deposited PVDF-TrFE  on the top of self-fabricated single-walled carbon nanotube transistors by inkjet  printing, a low-cost, solution based deposition process with good spatial  resolution. The fluoropolymer coated film was then annealed or heated in air at  140° Celcius for three minutes. Later, researchers observed the differences of device  characteristics. We found substantial performance improvements with the  fluoropolymer coated single-walled carbon nanotube both in device level and  circuit level, Dodabalapur noted. On the device level, significant  decreases occur in key parameters such as off-current magnitude, degree of  hysteresis, variation in threshold voltage and bias stress degradation, which  means a type of more energy-efficient, stable and uniform transistors with  longer life time. On the circuit level, since a transistor is the most basic  component in digital circuits, the improved uniformity in device  characteristics, plus the beneficial effects from individual transistors  eventually result in improved performance of a five-stage complementary ring  oscillator circuit, one of the simplest digital circuits "The oscillation  frequency and amplitude [of the single-walled carbon nanotube ring oscillator  circuit] has increased by 42% and 250% respectively" said  Dodabalapur. The parameters indicate a faster and better performing circuit  with possibly reduced power consumption. The improvements have been attributed  to the polar nature of PVDF-TrFE.
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