Organic memory device based on carbazole-substituted cellulose

A novel functionalized cellulose derivative, 6-O-[4-(9H-carbazol-9-yl)butyl]-2,3-di-O-methyl cellulose, has been synthesized and characterized. The photoluminescence spectrum of the as-cast film of the cellulose derivative exhibits sharp peaks with a well-defined vibronic structure, which indicates that the interaction between carbazole groups is rather weak. This is in contrast to the broad spectrum of a poly(N-vinylcarbazole) thin film. A thin-film device, where the cellulose derivative is sandwiched by two different metals, shows a drastic transition between mum low- and high-conductivity states upon the forward and backward sweeping of an external electric field. This reversible current density transition behavior demonstrates a typical memory characteristic, with the ON/OFF (high- and low- conductivity) states exhibiting a current ratio of about four orders of magnitude. The cellulose derivative with a functional group such as a carbazole moiety will be a candidate for organic electronic materials.