Printable electronics for polymer RFID applications

Abstract

Organic electronics create new opportunities of inexpensive RFID tag production techniques such as printing processes, which are only possible with soluble materials like polymers. Concepts for the production of fast integrated circuits based on p-type organic transistors have been demonstrated [1] using soluble polymers for active layer and insulating layer. A number of organic RFIDrelated building blocks and components have recently been published [2,[4][5][6][7]. This paper presents a passive organic transponder that uses a base-carrier frequency of 13.56MHz, designed for item-level tagging. The transponder prototype carries no ID and is mainly designed as a feasibility study. In the near future, data storage and implementation of a communication protocol will be pursued. Due to low charge carrier mobilities of µ≈0.02cm 2 /Vs the internal clock signal of the polymer-based transponder cannot be generated from the carrier signal as is done in many silicon-based RFID applications. The developed organic devices are air stable, even without encapsulation and all measurements were taken under ambient conditions. The manufacturing process of the transponder prototype is completely compatible with a printing process for mass production. The minimum structure size for printing is 20µm. Regarding the prototype transponder, all electrodes are patterned with a lithography mask using standard photolithography. The minimum structure size using this process is 5µm. The substrate for all devices is a flexible polyester film. Up to six different layers for Source/Drain-electrodes, polymer semiconductor for transistors, insulator for transistors, semiconductor for diodes, insulator for capacitors and gate-electrodes are applied. The field effect transistors (FET) are based on a top gate concept with source and drain consisting of a 40nm gold layer. The semiconducting layer of approximately 50nm thickness is applied by a spincoating process using a p-type soluble polymer poly 3-hexylthiophene (P3HT). A 300nm thick soluble organic copolymer blend is spincoated on as insulating layer [1]. Rectifier diodes are developed based on soluble poly 3-alcylthiophene (P3AT) as p-type semiconductor whereas anode and cathode are realized as metal contacts [2]. The capacitors are made with a proprietary blend of soluble insulating polymer between two metal electrodes. [1]. Copper was chosen in order to get high quality loop antennas that were structured by common etching techniques. Figure 15.1.1 shows the system overview of the reader that drives an organic transponder at a certain distance d. On the reader side a serial resonance circuit of reader loop antenna and a tuning capacitor is supplied by a signal generator that produces a 13.56MHz sine voltage with amplitude U g,p . The reader antenna has five turns of 10cm diameter and is matched to a 50Ω impedance.The transponder loop antenna in conjunction with the input capacitance of the organic rectifier represent a parallel resonance circuit that is tuned to the carrier frequency of 13.56MHz...

Plastic circuits and tags for 13.56MHz radio-frequency communication

“…In that work, lower bit generators (up to 6-bit) could be read out using a base carrier frequency of 13.56 MHz by a capacitive antenna. The ability to use organic electronics for inductively-coupled systems has been shown by Böhm et al [11], who demonstrated the read out of a ring oscillator using an inductive antenna. Ullmann field-effect transistors at 13.56 MHz [13].…”

An Organic FET SRAM With Back Gate to Increase Static Noise Margin and Its Application to Braille Sheet Display

“…Flexible and low-cost organic FETs (OFETs) are suitable for large-area electronics and have a potential as a supplement of solid and expensive silicon MOSFETs. OFETs have been applied to active-matrix displays [1]- [3], RF-ID transponders [4], [5], and sensors [6]- [10]. They are examples of the large-area electronics except for RF-ID.…”

Low‐Voltage Ring Oscillators Based on Polyelectrolyte‐Gated Polymer Thin‐Film Transistors

“…Many of the targeted applications for printed organic electronics require powering either from printed batteries, [6] solar cells, [7] or via electromagnetic induction. [8] Such power sources can typically supply an entire electronic system with a voltage ranging from 1 V to only a few volts at a current often limited to less than 1 mA. Moreover, the clock frequency should be at least 100 Hz for proper operation and rapid updating of the printed electronics.…”

“…Moreover, the clock frequency should be at least 100 Hz for proper operation and rapid updating of the printed electronics. [8] Hence, tremendous efforts are presently devoted to reducing the driving voltage of printable OTFTs simultaneously to keeping the delay time short. Figure 1 shows the lowest reported signal delay times per stage at different supply voltages (V DD ) for p-channel, [9][10][11][12][13][14][15] n-channel, [16] and complementary [17][18][19][20] OTFT circuits (ring oscillators).…”