A Fully Organic, Flexible, Ink-Jet Printed 8-Bit Tag for Radio-Frequency Applications

In last two decades, an increasing request of portable electronics, such as <b>Radio Frequency IDentification systems</b>, has paved the way for the development of new technologies for the fabrication of such devices at extremely low costs. If, on one hand, features like wireless and low-voltage operation and easiness-in-use are mandatory for these kind of systems, on the other, the possibility to integrate them into target objects, in a unperceivable way, has grown the interest on unconventional features such as mechanical flexibility and transparency.<br/><b>Organic electronics</b> can be considered as the natural candidate for the fabrication of such emerging devices, thanks to the intrinsic characteristics of the employed materials, not achievable with inorganic counterparts. Indeed, they are intrinsically flexible, transparent and solution-processable, thus being compatible with large areas and cost efficient deposition techniques, such as printing.<br/>However, severe constrains, especially poor performance at high frequencies when solution-processed materials are employed, still have limited the actual diffusion of organic devices.<br/>In this work, we report the first example of a <u>fully organic, printed 8-bit smart label tag for radio frequency applications</u>. The tag, the core of system, is based on complementary printed organic transistors, capable to operate at low voltages, and is entirely fabricated over flexible plastic substrate. The fabrication and operation of each building block (<b>flip-flops and shift register, diodes and rectificator, ring oscillator - for the clock generation - modulator</b> etc.) is discussed and presented, together with the operation of the whole system when coupled with a custom external reader, thus demonstrating the effective benchmark of the proposed tag for actual application. Moreover, <u>the system is fully fabricated through large area fabrication techniques</u>: <b>this achievement is of considerable interest for the so-called large-area electronics</b>, which goal is the scalability of the fabrication process by using cost-effective techniques, potentially compatible with large area fabrication and mass production, such as roll-to-roll and printing processes.