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 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. magnified image