Fluorenone/carbazole based bipolar small molecules for non-volatile memory devices

Abstract

Developing new-style non-volatile memory is an important part to solve von Neumann bottleneck. Among numerous studies of memory device, resistive random-access memory (RRAM) is widely researched for their simple geometrical structure and high integration density. In recent decades, organic RRAM catches many researchers’ attention for their superiorities such as outstanding flexibility, simple solution processability, low-cost fabrication and tunable functionalities by changing the chemical groups. Herein, a series of organic small molecules 2,7-di(9H-carbazol-9-yl)-9H-fluoren-9-one (FLOCZ) and 2,7-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-9H-fluoren-9-one (FLOBCZ) are synthesized and their band structures and electronic states are systematically studied with the assistance of density function theory (DFT). Then, using simple solution-processing approach, FLOCZ/FLOBCZ based RRAMs are fabricated and their memory characteristics are studied. The as-fabricated Ag/FLOBCZ/ITO RRAM exhibits non-volatile memory effect with a memory window up to 7 × 103 and data retention time of more than 2 × 104 s, which can meet the requirement of data storage. Meanwhile, by controlling compliance current on the RRAM precisely, multi-level data storage can be implemented experimentally. Our work extends the applications of organic small molecule and promotes the evolution of organic RRAM.