Intelligent packaging is an emerging technology, aiming to improve the standard communication function of packaging. Radio frequency identification (RFID) assisted smart packaging is of high interest, but the uptake is limited as the market needs cost-efficient and sustainable applications. The integration of screen printed antennas and RFID chips as smart labels in reusable cardboard packaging could offer a solution. Although paper is an interesting and recyclable material, printing on this substrate is challenging as the ink conductivity is highly influenced by the paper properties. In this study, the best paper/functional silver ink combinations were first selected out of 76 paper substrates based on the paper surface roughness, air permeance, sheet resistance and SEM characterization. Next, a flexible high frequency RFID chip (13.56 MHz) was connected on top of screen printed antennas with a conductive adhesive. Functional RFID labels were integrated in cardboard packaging and its potential application as reusable smart box for third party logistics was tested. In parallel, a web-based software application mimicking its functional abilities in the logistic cycle was developed. This multidisciplinary approach to developing an easy-scalable screen printed antenna and RFID-assisted smart packaging application is a good example for future implementation of hybrid electronics in sustainable smart packaging.
21 April 2014 in IEEE Transactions on Electron Devices
Fully printed organic field effect transistors (OFETs) are fabricated on a flexible, 100-μm-thick, polyethylene terephthalate substrate using high-throughput printing techniques: 1) Cyflex; 2) gravure; 3) screen; and 4) flexographic printing without using a cleanroom, and below 130°C. The dependence of the transconductance g m , transit-frequency f T, and intrinsic-gain on the bias drain current I D are measured. The OFETs show intrinsic gain for I D >10 nA mm (per millimeter width), and reach f T =64 kHz at I D = 16 μA/mm, whereas the g m loss with frequency is 10% up to f T . Unlike silicon MOSFETs, the dependence of the OFET g m on the f T in the subthreshold region is found to be weaker than I D1.0 . In addition, the overlap capacitance of the staggered-geometry OFET shows strong frequency dependence, and this is shown to be related to the overlap semiconductor. For the first time, it is found that the impact of process variations and bias stress on the OFET analog characteristics can be significantly attenuated by biasing the device at a fixed I D . This approach is tested on an array of five amplifiers, reaching the gain-bandwidth product of 32 kHz, within ±3.7% variations.
Resistive random-access memory is a candidate for next-generation non-volatile memory architectures. In this study, we use flexographic roll-to-roll printing technology for deposition of the resistive layer, a printing method that allows fast and cost-effective fabrication to create non-volatile resistive memory devices. Metal-free organic polymers blends composed of poly(methyl methacrylate) (PMMA) and a surplus of poly(vinyl alcohol) (PVA) serve as the active layer. Microscopic studies of the roll-to-roll printed layers show circular domains of PMMA embedded in PVA. The influence of the PMMA content in the polymer blend is investigated with respect to the performance and reliability of the resistive memory cells. Electrical characterization reveals a retention time of at least eleven days, a Roff/Ron ratio of approx. two orders and write/erase voltages of + 1/−2 V.
With a growing number of electronic devices surrounding our daily life, it becomes increasingly important to create solutions for clear and simple communication and interaction at the human machine interface (HMI). Haptic feedback solutions play an important role as they give a clear direct link and response to the user. This work demonstrates multifunctional haptic feedback devices based on fully printed piezoelectric transducers realized with functional polymers on thin paper substrate. The devices are flexible; lightweight and show very high out-of-plane deflection of 213 µm at a moderate driving voltage of 50 Vrms (root mean square) achieved by an innovative multilayer design with up to five individually controllable active layers. The device creates a very clear haptic sensation to the human skin with a blocking force of 0.6 N at the resonance frequency of 320 Hz, which is located in the most sensitive range of the human fingertip. Additionally the transducer generates audible information above two kilohertz with a remarkable high sound pressure level. Thus the paper-based approach can be used for interactive displays in combination with touch sensation; sound and color prints. The work gives insights into the manufacturing process; the electrical characteristics; and an in-depth analysis of the 3D deflection of the device under variable conditions