A transparent single-friction-surface triboelectric
generator and self-powered touch sensor†
Bo Meng, Wei Tang, Zhi-han Too, Xiaosheng Zhang, Mengdi Han, Wen Liu
and Haixia Zhang
*
We present a single-friction-surface triboelectric generator (STEG).
The STEG is transparent and flexible, making possible the use of
triboelectric generators in an extended range of applications. This
device is fabricated in a simple and very low-cost way. When tapped
with a finger, the STEG with micro-patterned PDMS surface achieved
an open-circuit voltage over 130 V with a short-circuit current density
of about 1 mAcm
2
. A STEG with a flat PET surface is employed as a
transparent cover on the screen of a smartphone to generate electric
energy from the control motion of the users. The STEG can directly
power 3 LEDs when the phone screen is tapped during normal use. In
addition, based on the STEG, we have developed a self-powered
visualized touch sensor with 4 STEGs serving as the touch pads. The
STEG shows promise for applications in systems such as self-powered
touch panels and artificial skins.
Introduction
Harvesting mechanical energy from the environment is widely
considered an attractive approach to provide a green energy
source for self-powered systems,
1,2
such as wireless sensor
networks, implanted medical devices, and other electronics.
Energy harvesters which convert mechanical energy into elec-
trical energy based on piezoelectric,
3–6
electromagnetic
7,8
and
electrostatic
9,10
operating principles have been developed.
Contact electrication is a well-known phenomenon that
occurs all around us in daily life. It has been studied for centuries
and applied in various ways.
11–14
In recent research, novel energy
harvesting devices termed triboelectric nanogenerators (TENGs)
have been developed.
15–28
These devices operate based on contact
electrication and electrostatic induction. TENGs can achieve
high output power density, which has made possible
applications in wireless systems,
18,19
portable electronics,
18
biomedical microsystems
20
and self-powered nanosensors.
27
Previously reported TENGs employed a typical structure
consisting of a pair of friction surfaces and two induction
electrodes, one for each friction surface. For this design, the
most e ffective way to improve the output power is to signi-
cantly separate the two friction surfaces either vertically or
laterally aer they are charged by contact electrication. Output
voltages of over 1000 V were reported in the recent research by
Wang's group,
21,24
a signicant increase in comparison to the
open-circuit voltage of only 18 V achieved in TENGs using an
inseparable structure.
16
However, implementing a large vertical or lateral separation
requires additional space, which will limit the applications of
separating structure TENGs.
In this work, we present a single-friction-surface triboelectric
generator (STEG). This device incorporates only one single
micro-structured PDMS or at PET friction surface. When an
active object such as nger, glove, pen, clothes, or similar
contacts the xed friction surface, the surface of the contacting
National Key Lab of Nano/Micro Fabrication Technology, Peking University, Beijing,
100871, China. E-mail: zhang-alice@pku.edu.cn
† Electronic supplementary information (ESI) available: The ESI contains 4
additional videos showing the applications of the STEG and the self-powered
touch sensor based on the STEG. See DOI: 10.1039/c3ee42311e
Cite this: Energy Environ. Sci. , 2013, 6,
3235
Received 10th July 2013
Accepted 14th August 2013
DOI: 10.1039/c3ee42311e
www.rsc.org/ees
Broader context
Harvesting mechani cal energy from the environment is widely considered
an attractive approach to provide a green energy source for self-powered
systems. Novel energy harvestin g devices based on contact electrication
and electrostatic induction have been developed and shown to achieve
high output power. In this work, a single-friction-surface triboelectric
generator (STEG) has been developed and characterized. The STEG can be
produced using a very simple fabrication process and makes possible the
use of TENGs in an extended range of applications. As the STEG device is
transparent and exible, they may prove an attractive power source for
exible electronics and portable devices. As a demonstration, a STEG was
applied as a transparent cover on the screen of a smartphone to generate
electrical energy during normal use of the smartphone touchscreen. A self-
powered touch sensor was developed using 4 STEGs as touch pads. This
self-powered device indicates which pad was touched on an LCD screen,
demonstrating the possibility that an array of STEG devices could poten-
tially be used to develop self-powered supersensitive touch panels and
articial skins.
This journal is ª The Royal Society of Chemistry 2013 Energy Environ. Sci., 2013, 6, 3235 –3240 | 3235
Energy &
Environmental Science
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