Polyaniline Nanofiber/Gold Nanoparticle Nonvolatile Memory

Abstract

A nonvolatile plastic digital memory device based on nanofibers of the conjugated polymer polyaniline decorated with gold nanoparticles is reported. The device has a simple structure consisting of the plastic composite film sandwiched between two electrodes. An external bias is used to program the ON and OFF states of the device that are separated by a 3-orders-of-magnitude difference in conductivity. ON-OFF switching times of less than 25 ns are observed by electrical pulse measurements. The devices possess prolonged retention times of several days after they have been programmed. Write-read-erase cycles are also demonstrated. The switching mechanism is attributed to an electric-field-induced charge transfer from the polyaniline nanofibers to the gold nanoparticles. The active polymer layer is created by growing nanometer size gold particles within 30-nm-diameter polyaniline nanofibers using a redox reaction with chloroauric acid. This device combines two exciting research areas--nanoparticles and conducting polymers--to form a novel materials system with unique functionality.

Synthesis and characterisation of controllably functionalised polyaniline nanofibres

“…More recently, interest has developed in the area of nanostructured polyaniline [15][16][17][18][19][20] . These one-dimensional objects 55 combine the advantages of an organic conductor and a high surface area material, thus making them suitable for a diverse range of applications such as chemical sensors, flash memory and electro-optic devices [21][22][23][24][25][26] . Derivatives of PAni have also been used to form 60 nanofibers, whereby monomers are first functionalised and then subsequently polymerised [27] .…”

Electrical Bistable Characteristics of Organic Charge Transfer Complex for Memory Device Applications

“…Recently, considerable attention has been directed toward electrical switching and memory devices which consist of organic materials, polymers and charge transfer complexes with an electrical bistable function [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Memory devices based on organic (polymer) materials have many advantages compared to inorganic memory devices, such as flexibility, simple processing, a low cost, and largearea fabrication via printing technology.…”

“…These conditions include a lower threshold voltage (<5 V), a higher ON/OFF ratio (>orders of 103), a rapid switching time (<100 ns), longer retention (>10 years at 60 o C), higher duration (>106 cycles) and a high memory capacity (>109 bite). Among the several types of organic (polymer) memory devices, such as trapping filling [13], filamentary conduction [14,15], electrochromicity [16], electroreduction and conformation changes of molecules [17,18], organic/metal/organic (O/M/O) structures [19][20][21][22] and charge transfer (CT) complex [23][24][25][26][27][28][29][30][31], last two organic (polymer) memory devices, organic/metal/organic (O/M/ O) structures and charge transfer (CT) complex, are entitled to be used for practical application. Especially, organic (polymer) memory devices based on the CT complex are expected to show fastest switching times (<10 ns), as the switching takes place via a rapid electronic process (redox reaction) rather than a slow process (chemical reaction, a conformational change, or isomerization), as reported in other memory devices.…”

“…After the Cu:TCNQ CT complex memory device was reported, several types of CT complex organic memory devices were reported by changing the copper metal donor with a different metal [24] or with an alkali-metal donor [25], or using new types of organic donors and acceptors [26,27] with different electron donating and accepting capabilities. In memory devices based on the CT complex, ON and OFF switching were realized by the formation and de-formation of the CT complex via an electron transfer between the donor and the acceptor [29][30][31]. Researchers also showed a fast switching time (<100 ns) and excellent device performance.…”

Optical and micro‐analytical study of a copper–conjugated polymer composite

“…Metal nanoparticles with different sizes and shapes combined with conducting polymers provides enhanced performance for both the host (polymer) and the guest (metal nanoparticles). This can lead to interesting physical properties and important potential applications [11] such as in non-volatile memory systems [12], resistors and diodes [13].…”