POS5-0882
Oxidative Chemical Vapor Deposition of Poly(3,4-ethylenedioxythiophene) Films for All-Plastic Organic Electrochemical Synaptic Transistors
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Hanheum Cho (Sungkyunkwan University)
Co-Author(s)
Abstract
Organic mixed ionic-electronic conductors (OMIECs) have attracted significant attention for energy-efficient neuromorphic devices, particularly in organic electrochemical synaptic transistors (OESTs) acting as artificial synaptic elements. While OESTs offer excellent ion-to-electron transduction capabilities, conventional fabrication relies on multi-step solution processes that typically exhibit low crystallinity. To address this challenge, oxidative chemical vapor deposition (oCVD) emerges as a promising vacuum-based process, enabling the fabrication of alkyl-chain-free and highly crystalline conducting polymer films with substrate non-selectivity. However, there is lack of research on systematic study on purity of precursors and its correlation to deposition conditions, i.g., morphologies and electrical characteristics, even though the purity of precursors is considered as key parameter in vacuum-based process for high quality films. In this study, the authors investigate the effects of monomer purity control to improve synaptic characteristics in a flexible monolithic junctionless OEST architecture with poly(3,4-ethylenedioxythiophene) films doped with chlorine (PEDOT:Cl). The authors discovered that identical PEDOT:Cl polymer films via different purity monomers affect synaptic behaviors, resulting from their different degree of molecular orientations. Polymer films with moderate crystallinity achieved via medium-purity monomer conditions exhibit semi-crystalline texture, resulting in enhanced linearity in synaptic behaviors. Specifically, the device fabricated with medium-purity monomers demonstrated outstanding memory retention, with the memory level declining only from 16.1% to 6.6%, outperforming those based on low-purity (15.1% to 4.2%) and high-purity (2.4% to 1.3%). Purity-mediated film morphology controls via oCVD provide an insight into characteristics tunability of OMIEC without complicated synthetic backbone or side-chain engineering.
