Polythiophene-based materials for nonvolatile polymeric memory devices

Abstract

Polymeric materials used in memory devices have attracted significant scientific interest due to their several advantages, such as low cost, solution processability, and possible development of three-dimensional stacking devices. Polythiophenes, including tethered alkyl substituted polythiophenes and block copolymers, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and composites, are one of the most attractive polymeric systems for memory applications because of their commercial availability, high conductivity, and mechanical strength. In this article, recent studies of functional polythiophene for memory applications are reviewed, mostly focusing on the role of the materials in the memory functionality, optimizing the chemical structure of the polythiophene and the component of each layer in memory device. A critical summary of the proposed mechanisms, including filament formation, electric field-induced charge transfer and reductionoxidation (redox) driven, is given to explain the resistive switching phenomena in the polythiophene system. In addition, the challenges facing the research and development in the field of polythiophene electronic memories are summarized. POLYM. ENG. SCI., 54:2470-2488, 2014. V C 2013 Society of Plastics Engineers INTRODUCTIONOver the past few decades, thin films of polymer semiconductors are being intensively investigated for electronics applications because of their remarkable advantages including their adaptability to low-temperature processing on flexible substrates, low cost, amenability to high-speed fabrication, and tunable electronic properties that are not feasible to produce using standard inorganic electronics. Polymer semiconductor devices such as light-emitting diodes [1], photovoltaic cells [2,3], thin-film transistors [4,5], chemical and photo sensors [6][7][8], organic/ polymer nonvolatile memory device [9] are potential candidates for future flexible electronic-device applications. Among these applications, polymer nonvolatile memory device appears highly attractive owing to its potential usage in data storage media. In particular, polymer memory devices have attracted a lot of attention due to their simple structure, three-dimensional stacking capability, good scalability, high mechanical flexibility [10,11]. Unlike current memory devices storing data by means of encoding "0" and "1" as the amount of charge stored in electric circuits, polymer nonvolatile devices store information in an entirely different manner, utilizing the conductivity response of the active layer to the applied voltage, in which the low and high resistive states are assigned to "ON" (or "LRS") and "OFF" (or "HRS"), respectively [12]. Among the nonvolatile memory types, the write-once read-many times (WORM) memory and the hybrid rewritable (write-read-erase-read) memory are usually observed in polymeric memory performance. Depending on the electrical polarity required for resistance switching, the switching behaviors can be classified into two types including polarity dep...

Efficient and Controlled Seeded Growth of Poly(3-hexylthiophene) Block Copolymer Nanofibers through Suppression of Homogeneous Nucleation

“…One of the most attractive conjugated polymers to use as a core-forming block for living CDSA methods is poly­(3-hexylthiophene) (P3HT) as a result of its widespread use in organic optoelectronic devices. − The self-assembly of amphiphilic P3HT BCPs has attracted much attention over the past decade. − However, attempts to implement ambient temperature living CDSA methods with BCPs such as P3HT- b -PDMS (PDMS = poly­(dimethylsiloxane)) and P3HT- b -P2VP (P2VP = poly­(2-vinylpyridine)) only allowed length control up to ca. 250–300 nm as a result of competing homogeneous nucleation (which led to the formation of new fibers) and rapid crystallization, which appeared to introduce defects into the growing micelle core. , Performing self-seeding experiments at temperatures that reduce the propensity for homogeneous nucleation and slow the rate of crystallization allowed access to low-dispersity fiberlike micelles with a P3HT core of length up to 1000 nm .…”

PTh/Co3O4 nanocomposites as new conducting materials for micro/nano‐sized electronic devices

“…Determining of the charge transport mechanism in the materials such as conducting polymers and its composites is therefore central in improving device performance and/or designing new devices. For instance, Li and Shen denoted that the transport mechanism of PTh plays an important role in the performance of the polymer based memory devices. Kline and McGehee also reported that the charge transport behavior of conjugated polymers is a determinative feature to photovoltaics and thin‐film transistors.…”

“…One of the aims of this study is to produce PTh/Co 3 O 4 nanocomposites with low cost, high conductivity and high thermal stability so that they can be used in various electronic applications. For instance, Li et al and Ashraf et al showed that PTh based composites with high conductivity can be used in polymeric memory devices, Li‐ion battery components and microelectronics. Another probably more important aim is to determine the ideal charge transport mechanism model of the PTh and its nanocomposites, which is important for developing new materials for various applications mentioned above.…”

Organic–Inorganic Nanocomposite Film for High‐Performance Stretchable Resistive Memory Device

“…Stretchable polymer-based resistive memories were an alternative to conventional inorganic semiconductor-based memory, due to their good flexibility for wearable device, [2,3] low cost, ease of processability, [4] and good scalability. [15] A number of polymeric materials, including polythiophene, [16] polyaniline, [17] polypyrrole, [18] poly(9-vinylcarbazole), [19] and poly(methyl methacrylate) [20] had been explored for polymer memory effects and applications. [15] A number of polymeric materials, including polythiophene, [16] polyaniline, [17] polypyrrole, [18] poly(9-vinylcarbazole), [19] and poly(methyl methacrylate) [20] had been explored for polymer memory effects and applications.…”

“…[5][6][7][8][9] These merits further accelerated the development of several types of polymer-based memory devices such as rewritable memory, [10][11][12][13] flash type, write once read many times (WORM)type memory, [14] and dynamic random access memory (DRAM). [15] A number of polymeric materials, including polythiophene, [16] polyaniline, [17] polypyrrole, [18] poly(9-vinylcarbazole), [19] and poly(methyl methacrylate) [20] had been explored for polymer memory effects and applications. Almost the entire aforementioned were utilized as polyelectrolytes, dye matrices, or component of a charge-transfer complex in a doping or blending system.…”