Page 217 - Science at the nanoscale

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June 5, 2009
9.4. Carbon Electronics
may reach its miniaturisation limits in a few decades, and we
may have to look for an alternative technology paradigm. One
question sometimes asked is: Will carbon ever replace silicon in
electronics? We summarize here the developments in organic elec-
tronics, molecular electronics, carbon nanotube electronics, and
most recently, graphene electronics.
Organic electronics, or plastic electronics, is a branch of elec-
tronics that deals with conductive polymers, plastics, or organic
molecules. The pioneers of highly-conducting organic polymers
are Alan J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa,
who were jointly awarded the Nobel Prize in Chemistry in 2000
for their 1977 discovery and development of oxidized, iodine-
doped polyacetylene.
Conducting polymers are lighter, more flexible, and less
expensive than inorganic conductors. Besides being a desirable
alternative in many applications, they also open up the possibil-
ity of new applications that would be impossible using inorgan-
ics. Organic light-emitting diodes (OLEDs) have already been
commercialised, and are being used in television screens, com-
puter displays, portable screens, advertising, and signboards. An
advantage of OLED displays over traditional liquid crystal dis-
plays (LCDs) is that OLEDs do not require a backlight to func-
tion. They draw far less power and, when powered from a battery,
can operate longer. OLED-based display devices also can be more
easily manufactured by printing methods, as compared to current
LCD and plasma display manufacturing technologies.
New applications in organic electronics include smart windows
and electronic paper. Smart window technology allows home
owners to block either all or some light by simply turning a knob
or pressing a button. This type of light control could potentially 207 ch09
save billions of dollars on heating, cooling and lighting costs. Elec-
tronic paper (or e-paper) mimics the appearance of ordinary ink on
paper. Unlike traditional displays, e-paper can be crumpled or
bent like traditional paper. Imagine the amount of trees saved if
our newspapers and books could be easily downloaded into our
personal e-paper!
The ultimate goal in device miniaturisation is to make devices
with a single molecule. Molecular electronics (or moletronics) is an
interdisciplinary field that spans physics, chemistry, and materials
science (cf. Section 1.3). The unifying theme is the use of molecu-
lar building blocks for the fabrication of electronic components.