Josephine B. Lee

Progress Toward Development of All-Printed RFID Tags: Materials, Processes, and Devices

Printed electronics provides a promising potential pathway toward the realization of ultralow-cost RFID tags for item-level tracking of consumer goods. Here, we report on our progress in developing materials, processes, and devices for the realization of ultralow-cost printed RFID tags. Using printed nanoparticle patterns that are subsequently sintered at plastic-compatible temperatures, low-resistance interconnects and passive components have been realized. Simultaneously, printed transistors with mobilities >10/sup -1/ cm/sup 2//V-s have been realized using novel pentacene and oligothiophene precursors for pMOS and ZnO nanoparticles for nMOS. AC performance of these devices is adequate for 135-kHz RFID, though significant work remains to be done to achieve 13.56-MHz operation.

Weave patterned organic transistors on fiber for E-textiles

Flexible transistors were formed directly on fibers in a novel weave-masking fabrication process. Pentacene fiber transistors exhibit mobilities of >0.5 cm/sup 2//V-s measured at 20 V V/sub DD/ and operate stably under a wide range of flexion stress. Devices are defined and positioned solely by a weaving pattern, meaning that simple circuits could potentially be directly built into fabric during manufacturing. This development offers a novel approach for providing information routing within fabric, which is currently a major hurdle in electronic textile development.

Printed organic transistors for ultra-low-cost RFID applications

Printed electronics provides a potential pathway toward the realization of ultra-low-cost radio frequency identification (RFID) tags for item-level tracking of consumer goods. Here, we report on our progress in developing materials and processes for the realization of printed transistors for low-cost RFID applications. Using inkjet printing of novel conductors, dielectrics, and organic semiconductors, we have realized printed transistors with mobilities >10/sup -1/cm/sup 2//V-s. AC performance of these devices is adequate for 135-kHz RFID, and, with further optimization, 13.56-MHz RFID appears to be within reach. We review the performance of these devices, and discuss optimization strategies for achieving the ultimate performance goals requisite for realizing ultra-low-cost printed RFID.

Arcuate sign of posterolateral knee injuries: anatomic, radiographic, and MR imaging data related to patterns of injury

ObjectiveThe “arcuate sign” is considered a pathognomonic sign for injuries of the posterolateral (PL) corner of the knee. The purpose of our study was to identify different patterns of injury to the fibular head that may associate with injuries to specific ligaments and tendons of the PL corner of the knee. The anatomic relations between the insertions of fibular collateral ligament (FCL), biceps femoris tendon (BFT), popliteofibular ligament (PFL), and arcuate ligament in normal cadaveric knees were also investigated.Design and patientsMagnetic resonance imaging was performed in two cadaveric knees which subsequently were dissected. Radiopaque markers were placed upon the fibular insertions of the FCL, BFT, PFL, and arcuate ligament in the dissected knees, and knee radiographs were then obtained. Twelve patients with radiographic or MR imaging evidence of isolated injury to the PL corner of the knee were retrospectively reviewed, with regard to avulsion fractures and marrow edema in the fibular head and the integrity of the ligaments of the PL corner of the knee.Results and conclusionsThe PFL and arcuate ligament were seen to attach directly to the posterior and medial aspect of the styloid process of the fibular head. The FCL and BFT attached as a conjoined structure on the lateral aspect of the fibular head lateral, anterior and inferior to the attachment site of the PFL and arcuate ligament. Injury to the arcuate ligament or PFL was diagnosed in 8 patients who presented with a small avulsion fracture of the styloid process of the fibula (n=2), bone marrow edema in the medial aspect of the fibular head (n=3), or both (n=3). In 4 patients with injury to the conjoined tendon or FCL, a larger avulsion fragment and more diffuse proximal fibular edema were seen. Radiographic and MR imaging findings in injuries of the posterolateral corner of the knee may suggest injury to specific structures inserting in the fibular head.

Organic transistors on fiber: a first step towards electronic textiles

For the first time, we demonstrate flexible transistors formed directly on fibers. This represents a significant step towards the realization of electronics textiles. Fiber transistors exhibit mobilities of >10/sup -2/ cm/sup 2//V-s measured at 20 V V/sub DD/. The entire transistor is fabricated without resorting to conventional lithography techniques. Patterning is achieved via shadowing from overwoven fibers. The process is compatible with textile manufacturing, and is therefore a promising technology for scalable e-textile fabrication.

10-nm channel length pentacene transistors

Organic thin-film transitors (OTFTs) were fabricated with channel lengths as small as 10 nm and an operating voltage of V/sub DD/=-0.3 V using e-beam lithography. For sub-200-nm channel lengths, scaling L downwards resulted in increased on-current, decreased I/sub on//I/sub off/ ratio, V/sub T/-rolloff, and drain-induced barrier lowering. These trends are correlated with device topology, electrostatics, and thin-film morphology. Nanoscale OTFT are interesting both as a means of studying intrinsic electrical properties of organic materials and as a possible route toward increasing on-current in organic devices. This paper sheds light on many of the issues encountered when shrinking organic devices, providing insight into approaches for optimizing nanoscaled OTFT.

A novel transparent air-stable printable n-type semiconductor technology using ZnO nanoparticles

We report on a novel, air-stable, printable, transparent, NMOS semiconductor technology using soluble ZnO nanoparticles. We demonstrate solution-processed transistors with mobility > 0.1 cm/sup 2//V/spl middot/s, which is the highest solution-processed NMOS mobility reported to date. The air-stability and transparency make this device an ideal candidate for low-cost printed displays and CMOS circuitry.

All-printed RFID tags: materials, devices, and circuit implications

Printed electronics holds promise for realizing ultra-low-cost RFID tags for item-level tracking of consumer goods. We report on our progress in developing all-printed RFID tags. We review the development of printable materials for these applications, summarize the characteristics of printed devices, and discuss the implications of these on circuit performance limits and needs. Based on this assessment, we discuss the outlook for all-printed RFID tags and identify the problems remaining to be solved and the efforts taking place in this regard.

Printed Electronic Nose Vapor Sensors for Consumer Product Monitoring

Embedded sensors based on printed organic semiconductors are attractive for use in product content monitoring due to their low cost. Arraying multiple sensor elements, in a bridge topology, yields signatures that achieve high specificity using non-specific elements. The output signal is amplified and digitized to detect numerous analytes with up to 10ppm sensitivity. A wine-spoilage application is demonstrated

Printed organic transistors for low-cost RFID applications

Printed electronics is attractive as a pathway towards the realization of ultra-low-cost RFID tags for replacement of conventional optical barcodes. While this application has received tremendous attention in recent years, it also represents one of the most challenging applications for organic transistors, based on both the performance requirements and the process complexity and cost implications. Here, we report on our progress in developing materials and processes for the realization of printed transistors for low-cost RFID applications. Using inkjet printing of novel conductors, dielectrics, and organic semiconductors, we have realized printed transistors with mobilities >0.1cm2/V-s, which is approaching the requirements of certain RFID applications. We review the performance of these devices, and discuss optimization strategies for achieving the ultimate performance goals requisite for realizing printed RFID.