Covalent Modification of Graphene Oxide with Poly(N-vinylcarbazole) Containing Pendant Azobenzene Chromophores for Nonvolatile Ternary memories

Abstract Nonvolatile resistive random access memory (RRAM) with large ON/OFF ratio characteristics and digital-type current switching has inspired tremendous amount of research interests over the past years. Herein we designed and synthesized a novel graphene oxide (GO) functionalized with poly(N-vinylcarbazole) containing pendant azobenzene chromophores (PVK-AZO-GO), in which the pendant carbazole moieties, azobenzene chromophores and GO act as electron donor (D), charge trap (T) and electron acceptor (A), respectively. The as-prepared memory device with a configuration of Al/PVK-AZO-GO/ITO exhibited a nonvolatile ternary write-once-read-many-times (WORM) memory effect due to the field-induced charge-transfer interaction between the carbazole moieties (D) and the GO unit (A), and subsequent charge trapping at the intermediate azobenzene chromophores (T). The achieved OFF: ON1: ON2 current ratio reached up to 1: 10 1.6 : 10 4.5 . This work provides a novel design approach for ternary memory materials that can greatly enhance the storage capacity of polymer memory devices.