Boolean and Elementary Algebra with a Roll‐To‐Roll Printed Electrochemical Memristor

Abstract

memory component in a von Neumann computer architecture [3] and have, especially in the case of inorganic systems, proven to be suitable for storing and processing information with numerous excellent attributes. [2] The memory requirements for a von Neumann computer architecture differ greatly from biologically inspired synaptic functions, where synaptic weights are modulated by the number and frequency of homogeneous spikes and take a continuity of values. A number of review papers [4][5][6][7][8] have been presented that focus on memristors intended for neuromorphic applications and all share the common theme, that in this role, memristors must exhibit reliable analog properties including non-abrupt switching transitions, continuously variable resistance states, and a predictable response. Compared to their inorganic counterparts, organic materials have several advantages when it comes to fabrication and implementation as a neuromorphic device. Organic materials can be integrated to largescale production with low-cost manufacturing processes and high resolution lithography patterning along with tailoring the chemistry to desired chemical, electrical and mechanical properties. [7,8] These traits allow memristor devices to provide a simple and effective route for fabricating physical artificial neural networks which are independent of software programming. [9,10] A non-volatile conjugated polymer-based electrochemical memristor (cPECM), derived from sodium 4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy] butane-2-sulfonate (S-EDOT), is fabricated through roll-to-roll printing and exhibited neuromorphic properties. The 3-terminal device employed a "read" channel where conductivity of the water-soluble, self-doped S-PEDOT is equated to synaptic weight and was electrically decoupled from the programming electrode. For the model system, a +2500 mV programming pulse of 100 ms duration resulted in a 0.136 μS resolution in conductivity change, giving over 1000 distinct conductivity states for one cycle. The minimum programming power requirements of the cPECM was 0.31 pJ mm −2 and with advanced printing techniques, a 0.1 fJ requirement for a 20 μm device is achievable. The mathematical operations of addition, subtraction, multiplication, and division are demonstrated with a single cPECM, as well as the logic gates AND, OR, NAND, and NOR. This demonstration of a printed cPECM is the first step toward the implementation of a mass produced electrochemical memristor that combines information storage and processing and may allow for the realization of printable artificial neural networks.

Nonconformal Electrochemical Memristor through Vapor Phase Polymerization of Pyrrole

“…Similar device fabrication has been previously reported. 4 In short, indium tin oxide (ITO)-coated glass (Part Number: CG-50IN-S107) was purchased from Delta Technologies, Limited, with a sheet resistance of 8−12 Ω/sq. In order to remove any unwanted ITO, both the top and bottom synaptic electrodes were acid-etched by using hydrochloric acid (36%) poured over zinc metal.…”

“…The bottom synaptic electrode was templated using a positive photoresist such that a channel length of The well is filled in with a PEG-based gel containing a tetrabutylammonium hexafluorophosphate (Bu 4 NPF 6 ) electrolyte. 4 The electrolyte is photopolymerized with an ELC-500 light exposure system to properly seal and mate the top and bottom slides. The aluminum (Al) electrodes used on the nonconformal toy car device were deposited via a Denton DV-502a thermal evaporator after templating and masking the car with polyimide tape.…”

“…By varying the (de)­doping levels of each layer, various redox-active species can be implemented into these 3-terminal synaptic-like memristive devices, which will exhibit neuromorphic computation attributes. Another recent report presents a 3-terminal conjugated polymeric-based electrochemical memristor (cPECM) where, utilizing a PEDOT derivative that is self-doped and water-soluble, both Boolean algebra and elementary algebra were implemented to demonstrate the device’s potential as a candidate for neuromorphic computers . To that end, a 3-terminal conjugated polymeric organic synaptic memristive device is presented in this effort that utilizes a VPP deposition of polypyrrole (PPy) over conformal and nonconformal substrates.…”

“…Another recent report presents a 3-terminal conjugated polymeric-based electrochemical memristor (cPECM) where, utilizing a PEDOT derivative that is selfdoped and water-soluble, both Boolean algebra and elementary algebra were implemented to demonstrate the device's potential as a candidate for neuromorphic computers. 4 To that end, a 3-terminal conjugated polymeric organic synaptic memristive device is presented in this effort that utilizes a VPP deposition of polypyrrole (PPy) over conformal and nonconformal substrates. The PPy-based synaptic memristor is capable of achieving highly distinct and symmetric linear conductance states that can be tailored into neuromorphic and advanced operational techniques.…”

Temperature‐triggered oxidative polymerization for high conductive poly(3,4‐ethylenedioxythiophene) sheets at millimeter scale

“…To overcome these issues, there proposed two ways to improve hydrophilicity or lipophilicity of PEDOT. One is introducing additional functional groups such as alkyl chains 10,11 and sulfonates, 12,13 and the other is grafting PEDOT chains onto auxiliary substances 14 or soluble polymers. 15 A significant advance for the commercial application of PEDOT-based conductive materials is the PEDOT:PSS emulsions 16 developed by the German company Bayer, which uses polystyrene sulfonate (PSS) as auxiliary polymer.…”