Isoindigo-Based Donor–Acceptor Conjugated Polymers\nfor Air-Stable Nonvolatile Memory Devices

Abstract

Nonvolatile\nresistive memory devices based on a new low bandgap\ndonor–acceptor (D–A) conjugated polymer, poly­((<i>E</i>)-6,6′-bis­(2,3-dihydrothieno­[3,4-<i>b</i>]­[1,4]­dioxine-5-yl)-1,1′-bis­(2-octyldodecyl)-[3,3′-biindolinyi-dene]-2,2′-dione)\n(PIDED), which are fabricated and operated in ambient air, are reported.\nThe D–A conjugated polymer is synthesized from 2,3-dihydrothieno­[3,4-<i>b</i>]­[1,4]­dioxine and isoindigo as an electron donor and an\nelectron acceptor, respectively, using CH-arylation polymerization.\nThe devices show nonvolatile, unipolar resistive switching behaviors\nwith a high on/off current ratio (∼10⁴), excellent\nendurance cycles (>200 cycles), and a long retention time (>10⁴ s) in ambient air. These properties remain stable in ambient\nair over one year, demonstrating that the device performance is significantly\nunaffected by exposure to air as the isoindigo has strong electron-withdrawing\ncharacter and the PIDED exhibits a high degree of crystallinity. This\nstudy may pave the way for use of practical nonvolatile organic memory\ndevices operating in ambient air.