TECH KNOWLEDGEY
EVENTS, ADVANCES, AND NEWS
2011
■ BY JEFF ECKERT
ADVANCED TECHNOLOGY
DEVICE GETS JUICE FROM
HEAT AND LIGHT
The idea of deriving electricity from ambient light, heat, vibrations, EM
waves, and so on has attracted
increased interest over the last few
years. However, the amount of power
available from such sources is limited as
compared to what we can draw from
power plants and batteries, and a device
that harnesses only one ambient source
has a corresponding limit on its output.
Therefore, a device that draws off two or
more of these simultaneously would
have obvious advantages.
At the IEEE International Electron Devices Meeting
last December, Fujitsu Labs ( jp.fujitsu.com/group/
labs/en/) announced the development of such a hybrid
device which can generate electricity from either heat or
light. According to Fujitsu, the material is efficient enough
to produce power even from indoor lighting (in the
photovoltaic mode) and from heat in its thermoelectric
mode.
By changing the electrical circuits connecting two
types of semiconductor materials (P- and N-type), the
device can function as a photovoltaic cell or
■ A single device operates in both photovoltaic (left) and
thermoelectric (right) modes.
thermoelectric generator. As a potential application, the
company cites sensors that are used to monitor such
things as body temperature, blood pressure, pulse, and
so on. Such devices could be powered by either light or
heat, and if either one is insufficient, one source could
be used to augment the other. An added benefit is that
it can be manufactured from cheap organic materials,
so production costs should remain low. Fujitsu will
continue to develop the concept for increased
performance and hopes to commercialize the technology
by 2015. ▲
DISPOSABLE E-BOOKS?
As you've probably noticed, the price of e-readers has plummeted over the last year or so. A case in point is Amazon's Kindle which hit the market in 2007 at $399 but now is priced at $139 ($189 for the 3G + WiFi version). Now, an
engineering researcher at the University of Cincinnati ( www.uc.edu) has come up with a concept that could make
e-readers so cheap that they could be considered disposable. It seems that Prof. Andrew Steckl's research into an
affordable, high performance, paper-based display technology has paid off. As described in a recent issue of the
American Chemical Society journal Applied Materials and Interfaces, the breakthrough is based on using paper as a
flexible host material for an electrowetting device. The electrowetting process involves applying an electric field to
colored droplets in the display, thereby generating images ranging from simple type to photos and even video.
According to Steckl, "One of the main goals of e-paper is to replicate the look and feel of actual ink on paper. We
have, therefore, investigated the use of paper as the perfect substrate for EW devices to accomplish e-paper on paper ...
It is pretty exciting. With the right paper, the right process, and the right device fabrication technique, you can get results
that are as good as you would get on glass, and our results are good enough for a video-style e-reader."
The goal is to achieve a material that can be rolled out like a paper towel, produce even high res color video, and still
be tossed when you're done with it. Steckl predicts that it will take three to five years to reach commercialization, so the
relatively expensive, glass-based readers will be around for a while. ▲
10
February 2011
