Polarity Effects of Polymer Gate Electrets on Non‐Volatile Organic Field‐Effect Transistor Memory
TL;DR: An electret is a piece of dielectric material that exhibits aquasi-permanent electrical charges or dipolar polarization, including ferro-, piezo-, and pyro-electric polymers as discussed by the authors.
Abstract: These func-tionalities arise from field-effect modulation by the chargesstored in chargeable polymer gate dielectrics, referred to aspolymer electrets.An electret is a piece of dielectric material that exhibits aquasi-permanent electrical charges or dipolar polarization,including ferro-, piezo-, and pyro-electric polymers.
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TL;DR: The history, current status of research, main challenges and prospects for functional OFETs are all discussed, in order to provide a comprehensive overview of this field.
Abstract: Functional organic field-effect transistors (OFETs) have attracted increasing attention in the past few years due to their wide variety of potential applications. Research on functional OFETs underpins future advances in organic electronics. In this review, different types of functional OFETs including organic phototransistors, organic memory FETs, organic light emitting FETs, sensors based on OFETs and other functional OFETs are introduced. In order to provide a comprehensive overview of this field, the history, current status of research, main challenges and prospects for functional OFETs are all discussed.
518 citations
TL;DR: In this article, the role of π-conjugated materials in the operation of nonvolatile memory devices is reviewed and a review of the state of the art with respect to these target specifications is presented.
Abstract: Organic molecules and semiconductors have been proposed as active part of a large variety of nonvolatile memory devices, including resistors, diodes and transistors. In this review, we focus on electrically reprogrammable nonvolatile memories. We classify several possible devices according to their operation principle and critically review the role of the π-conjugated materials in the device operation. We propose specifications for applications for organic nonvolatile memory and review the state of the art with respect to these target specifications. Conclusions are drawn regarding further work on materials and device architectures.
487 citations
TL;DR: In this paper, the authors provide an overview of the physical effects that cause hysteresis and discuss the importance of such effects in OFETs in a comparative manner, in order to provide a comprehensive picture of the hystresis phenomena in organic field effect transistors.
Abstract: Research into organic field effect transistors (OFETs) has made significant advances—both scientifically and technologically—during the last decade, and the first products will soon enter the market. Printed electronic circuits using organic resistors, diodes and transistors may become cheap alternatives to silicon-based systems, especially in large-area applications. A key parameter for device operation, besides long term stability, is the reproducibility of the current–voltage behavior, which may be affected by hysteresis phenomena. Hysteresis effects are often observed in organic transistors during sweeps of the gate voltage (V
GS). This hysteresis can originate in various ways, but comparative scientific investigations are rare and a comprehensive picture of “hysteresis phenomena” in OFETs is still missing. This review provides an overview of the physical effects that cause hysteresis and discusses the importance of such effects in OFETs in a comparative manner.
283 citations
TL;DR: In this paper, the crystal packing, charge transport, and assembly protocols of organic crystalline materials (OCMs) are introduced, and state-of-the-art construction strategies for aligned/patterned OCM on/into flexible substrates are discussed in detail.
Abstract: Flexible electronics have attracted considerable attention recently given their potential to revolutionize human lives. High-performance organic crystalline materials (OCMs) are considered strong candidates for next-generation flexible electronics such as displays, image sensors, and artificial skin. They not only have great advantages in terms of flexibility, molecular diversity, low-cost, solution processability, and inherent compatibility with flexible substrates, but also show less grain boundaries with minimal defects, ensuring excellent and uniform electronic characteristics. Meanwhile, OCMs also serve as a powerful tool to probe the intrinsic electronic and mechanical properties of organics and reveal the flexible device physics for further guidance for flexible materials and device design. While the past decades have witnessed huge advances in OCM-based flexible electronics, this review is intended to provide a timely overview of this fascinating field. First, the crystal packing, charge transport, and assembly protocols of OCMs are introduced. State-of-the-art construction strategies for aligned/patterned OCM on/into flexible substrates are then discussed in detail. Following this, advanced OCM-based flexible devices and their potential applications are highlighted. Finally, future directions and opportunities for this field are proposed, in the hope of providing guidance for future research.
274 citations
TL;DR: In this paper, a solution-processed poly[9,9-dioctylfluorenyl-2,7-diyl]-co-(bithiophene)] (F8T2) nano floating gate memory (NFGM) with a top-gate/bottom-contact device configuration is reported.
Abstract: Organic field-effect transistor (FET) memory is an emerging technology with the potential to realize light-weight, low-cost, flexible charge storage media. Here, solution-processed poly[9,9-dioctylfluorenyl-2,7-diyl]-co-(bithiophene)] (F8T2) nano floating gate memory (NFGM) with a top-gate/bottom-contact device configuration is reported. A reversible shift in the threshold voltage (V Th ) and reliable memory characteristics was achieved by the incorporation of thin Au nanoparticles (NPs) as charge storage sites for negative charges (electrons) at the interface between polystyrene and cross-linked poly(4-vinylphenol). The F8T2 NFGM showed relatively high field-effect mobility (μ FET ) (0.02 cm 2 V -1 s -1 ) for an amorphous semiconducting polymer with a large memory window (ca. 30 V), a high on/off ratio (more than 10 4 ) during writing and erasing with an operation voltage of 80 V of gate bias in a relatively short timescale (less than 1 s), and a retention time of a few hours. This top-gated polymer NFGM could be used as an organic transistor memory element for organic flash memory.
249 citations
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TL;DR: The future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.
Abstract: Organic electronics are beginning to make significant inroads into the commercial world, and if the field continues to progress at its current, rapid pace, electronics based on organic thin-film materials will soon become a mainstay of our technological existence. Already products based on active thin-film organic devices are in the market place, most notably the displays of several mobile electronic appliances. Yet the future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.
4,967 citations
IBM1
TL;DR: In this article, the authors present new insight into conduction mechanisms and performance characteristics, as well as opportunities for modeling properties of organic thin-film transistors (OTFTs) and discuss progress in the growing field of n-type OTFTs.
Abstract: Organic thin-film transistors (OTFTs) have lived to see great improvements in recent years. This review presents new insight into conduction mechanisms and performance characteristics, as well as opportunities for modeling properties of OTFTs. The shifted focus in research from novel chemical structures to fabrication technologies that optimize morphology and structural order is underscored by chapters on vacuum-deposited and solution-processed organic semiconducting films. Finally, progress in the growing field of the n-type OTFTs is discussed in ample detail. The Figure, showing a pentacene film edge on SiO2, illustrates the morphology issue.
4,804 citations
IBM1
TL;DR: In this article, a review of the materials used in switching devices is presented, focusing particularly on the role of filamentary conduction and deliberately introduced or accidental nanoparticles, and the reported device parameters (on-off ratio, on-state current, switching time, retention time, cycling endurance, and rectification) are compared with those that would be necessary for a viable memory technology.
Abstract: Many organic electronic devices exhibit switching behavior, and have therefore been proposed as the basis for a nonvolatile memory (NVM) technology. This Review summarizes the materials that have been used in switching devices, and describes the variety of device behavior observed in their charge-voltage (capacitive) or current-voltage (resistive) response. A critical summary of the proposed charge-transport mechanisms for resistive switching is given, focusing particularly on the role of filamentary conduction and of deliberately introduced or accidental nanoparticles. The reported device parameters (on-off ratio, on-state current, switching time, retention time, cycling endurance, and rectification) are compared with those that would be necessary for a viable memory technology.
964 citations