Isoindigo-Based Donor-Acceptor Conjugated Polymers for Air-Stable Nonvolatile Memory Devices.

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