Katherina Haase

Naphtalenediimide-based donor–acceptor copolymer prepared by chain-growth catalyst-transfer polycondensation: evaluation of electron-transporting properties and application in printed polymer transistors

The semiconducting properties of a bithiophene-naphthalene diimide copolymer (PNDIT2) prepared by Ni-catalyzed chain-growth polycondensation (P1) and commercially available N2200 synthesized by Pd-catalyzed step-growth polycondensation were compared. Both polymers show similar electron mobility of ∼0.2 cm2 V−1 s−1, as measured in top-gate OFETs with Au source/drain electrodes. It is noteworthy that the new synthesis has several technological advantages compared to traditional Stille polycondensation, as it proceeds rapidly at room temperature and does not involve toxic tin-based monomers. Furthermore, a step forward to fully printed polymeric devices was achieved. To this end, transistors with PEDOT:PSS source/drain electrodes were fabricated on plastic foils by means of mass printing technologies in a roll-to-roll printing press. Surface treatment of the printed electrodes with PEIE, which reduces the work function of PEDOT:PSS, was essential to lower the threshold voltage and achieve high electron mobility. Fully polymeric P1 and N2200-based OFETs achieved average linear and saturation FET mobilities of >0.08 cm2 V−1 s−1. Hence, the performance of n-type, plastic OFET devices prepared in ambient laboratory conditions approaches those achieved by more sophisticated and expensive technologies, utilizing gold electrodes and time/energy consuming thermal annealing and lithographic steps.

Modified poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) source/drain electrodes for fully printed organic field-effect transistors consisting of a semiconductor blend

The influence of post-press treatment on the modification of printed source/drain electrodes made of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with ethylene glycol is presented. Beside changes of the geometry and the conductivity of these mass printed structures, the work function of PEDOT:PSS can be tuned, leading to an improved performance of organic field effect transistors (OFETs). OFETs were built up with a new small molecule/polymer blend consisting of 6,13-bis[(cyclopropyldiisopropylsilyl)ethynyl] pentacene and poly(triarylamine), providing a field effect mobility of 0.2u2009cm2/Vs for fully printed devices in air. Ring oscillators based on these OFETs demonstrate a frequency of more than 1 kHz.

A Fully-Printed Self-Biased Polymeric Audio Amplifier for Driving Fully-Printed Piezoelectric Loudspeakers

In this paper, a printed audio amplifier, which is a new application for organic electronics, is suggested. The amplifier consists of several fully-printed bendable components including: a loudspeaker, organic field effect transistors (OFETs), capacitors, and resistors. All components are fabricated on polyethylene terephthalate (PET) substrate by means of high-throughput printing techniques. A complete self-biased circuit is reported consisting of large multi-finger OFETs with channel length of 20 μm and total width of 0.475 meter. The amplifier provides a peak voltage gain of 18 dB at 400 Hz, can reproduce sound pressure level of 36-60 dBA over 700 Hz to 12.5 kHz at one meter distance, and has a unity-gain-bandwidth of 17.7 kHz/5.2 kHz when driving 0 nF/~39 nF load at VDD = 80 V, respectively. The impact of bias-stress effects on the amplifier performance is measured to be ~3 dBA sound loss after 5 hours of continuous operation. The whole circuit is packaged and laminated on a separate PET sheet. In addition, the intrinsic electrical impedance of the printed PVDF-TrFE piezoelectric polymer used in the loudspeaker is characterized, and is modeled by a complex dielectric constant.

Bending and Folding Effect Study of Flexible Fully Printed and Late-Stage Codified Octagonal Chipless RFID Tags

In this paper, octagonal chipless RFID tags are introduced and herein, the design development, the applied fabrication, and the experimental verification are presented. The designed tags, which are based on frequency-selective surfaces, are produced by screen printing on low-cost flexible materials including plastic and paper. A novel codification technique specifically conceived to complement the high yield manufacturing processes is proposed. Through an extensive measurement campaign, the octagonal chipless RFID tag functionality is proved. The experimental results include the morphological characterization, ID code verification, and a complete study of the bending and folding effects on the tag. Focusing on this, a working bent tag with a curvature radius down to 16 mm is reviewed. Additional characteristics like the polarization independence and extended read ranges are also corroborated.

Automatic IR UWB chipless RFID system for short range applications

The decoding of ultra-wide band (UWB) chipless radio frequency identification (RFID) tags is often performed extracting its frequency response, by removing the channel contribution. In this paper, an automatic short range (< 50 cm) ultra-wide band (UWB) impulse radio (IR) chipless (RFID) system is proposed. The system is composed of four different coded 5-bits UWB chipless RFID tags fabricated by printing silver ink on a polyethylene terephthalate (PET) substrate, and an impulse radio (IR) UWB radar available commercially. A novel decoding algorithm is implemented to scan the interrogation zone, detect when an UWB chipless RFID tag is placed, and then proceed to identify it without the need of a reference or channel measurement in a line-of-sight, multipath free scenario. The decoding is based on a maximum likelihood (ML) rule to estimate the received UWB chipless RFID tag code embedded in the backscattered pulse. The different UWB chipless RFID tags are successfully decoded automatically, verifying the viability of this methodology.

Design of Printed Chipless-RFID Tags With QR-Code Appearance Based on Genetic Algorithm

In this paper, the design of the chipless-Radio Frequency Identification (RFID) tags based on genetic algorithm (GA) optimization techniques is introduced. The GA is applied for the first time to create a family of frequency-domain chipless tags with a quick responselike appearance. The resultant tags have an area of 30 mm <inline-formula> <tex-math notation=LaTeX>

Fully printed flexible audio system on the basis of low‐voltage polymeric organic field effect transistors with three layer dielectric

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Small-signal characteristics of fully-printed high-current flexible all-polymer three-layer-dielectric transistors

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Square-shape fully printed chipless RFID tag and its applications in evacuation procedures

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Solution Coating of Small Molecule/Polymer Blends Enabling Ultralow Voltage and High-Mobility Organic Transistors

</tex-math></inline-formula> element array creating a variety of new structures. The frequency signature of the GA-based tags is optimized to fit with a frequency-shift keying-based coding methodology and a capacity of 8 b is achieved. The performance of the resultant tags is experimentally verified. Optimal tag samples are fabricated using silver-ink, low-cost flexible substrates, and by screen printing, which is a mass-compatible production technique. The feasibility of this optimization technique for the design of chipless-RFID tags is corroborated.