Organic Ferroelectric Molecule Developed As An Alternative To Silicon For Semiconductors

Electrical response overlaid on the newly characterized organic molecular crystal.
Credit: Jiangyu Li, University of Washington

Diisopropylammonium bromide is a new organic molecule synthesized from bromine, carbon, hydrogen and nitrogen that may be an alternative to silicon for use in semiconductors and other memory, sensing and low-cost energy storage applications.

Organic molecules are molecules that contain carbon. Carbon is a versatile atom and can attach easily to other atoms (forming 4 covalent bonds). The science of designing, synthesizing, characterizing, and developing applications for molecules that contain carbon is called organic chemistry.

Organic molecules are often associated with living things but for organic compounds this is not necessarily the case. The term comes from the old belief that certain compounds and molecules require a "life-force" of a living thing to be generated. The belief has been discredited but the term still remains.

Organic chemistry applications range from the medical to the industrial. One role of organic chemists is to synthesize and develop new molecules that will address a problem or enhance a product.

Synthetic organic compounds usually carry properties that enhance a process, mitigate or address a design/process flaw, or solve a problem. Most of these applications can be seen in pharmaceutical and consumer products.

Non-Volatile Ferroelectric Memory Developed To Address Upkeep of Cloud Computing

Ferroelectricity is the property of some materials to store a permanent electric field. Ferroelectric RAM (Random Access Memory) or FRAM is a memory technology. It combines the technologies behind RAM and ROM (Read Only Memory).

FRAM is high performance, non-volatile memory that can be used in many applications. Smart cards, security, metering and RFID are some of the applications that can benefit from FRAM.

Major advantages of Ferroelectric RAM over EEPROM and Flash is its speed, endurance, low power consumption, security, and tolerance for radiation. In actual lab tests, FRAM has proven to process information faster than other RAM technologies. It also has a high endurance with an estimated 317 years.

Ferroelectric materials could bring down cost of cloud computing and electronic devices

A new class of organic materials developed at Northwestern University boasts a very attractive but elusive property: ferroelectricity. The crystalline materials also have a great memory, which could be very useful in computer and cellphone memory applications, including cloud computing.

A team of organic chemists discovered they could create very long crystals with desirable properties using just two small organic molecules that are extremely attracted to each other. The attraction between the two molecules causes them to self assemble into an ordered network -- order that is needed for a material to be ferroelectric.

The starting compounds are simple and inexpensive, making the lightweight materials scalable and very promising for technology applications. In contrast, conventional ferroelectric materials -- special varieties of polymers and ceramics -- are complex and expensive to produce. The Northwestern materials can be made quickly and are very versatile.

In addition to computer memory, the discovery of the Northwestern materials could potentially improve sensing devices, solar energy systems and nanoelectronics. The study will be published Aug. 23 by the journal Nature.

"This work will serve as a guide for designing these materials and using ferroelectricity in new ways," said Samuel I. Stupp, Board of Trustees Professor of Chemistry, Materials Science and Engineering, and Medicine. He is a senior author of the paper. "Our molecular design enables us to invent a nearly infinite library of ferroelectric materials."

Ferroelectric materials exhibit spontaneous electric polarization (making one side of the material positive and the opposite side negative) that can be reversed by the application of an electric field (from a battery, for example). These two possible orientations make the materials attractive to researchers developing computer memory because one orientation could correspond to a 1 and the other to a 0. (Computer memory stores information in 1's and 0's.)

"The material's behavior is complex, but the superstructure is simple," said Sir Fraser Stoddart, Board of Trustees Professor of Chemistry in the Weinberg College of Arts and Sciences at Northwestern. He also is a senior author. "It is the superstructure that gives the material its desirable properties."