Nitronyl Nitroxide Radicals as Organic Memory Elements with Both n- and p-Type Properties

摘要

Organic molecules are being actively explored for use in logical devices, either as individual memory elements or as components embedded in small organic and polymeric materials. Conventional inorganic semiconductor devices are limited in terms of performance improvement owing to increased costs for device fabrication as well as physical limitations on minimum feature dimensions. Organic memory, however, is a possible substitute for both volatile and non-volatile memory devices. It has the advantages of facile tailoring through organic synthesis, simple device fabrication (even upon flexible substrates), and very low power consumption. Volatile organic memory is expected to be applied towards dynamic random access memory (DRAM), which typically requires a data refresh every few milliseconds, while non-volatile organic memory, can be applied to read-only memory (ROM) and flash-type memory. Several types of organic and polymeric materials have been reported for this purpose, such as organic semiconductors, charge-transfer complexes (including redox-active compounds), and metal-nanoparticle-dispersed thin films. Recently, a new type of organic memory has been added to this list, namely organic radical molecules (nitroxide radicals, NO') that contain an unpaired electron that is capable of undergoing oxidation or reduction by applied bias voltages.