石墨烯-PVK信息存儲論文被Nature Publishing Group-Asia Materials HIGHLIGHT
華東理工大學陳彧教授課題組和新加坡國立大學E.T. Kang教授課題組聯合發表在Appl. Phys.Lett. 上的論文（Liu, G.,Zhuang, X., Chen, Y.*, Zhang, B., Zhu, J.,
Zhu, C.-X., Neoh, K.-G. & Kang, E.-T.* Bistable electrical switching and electronic memory
effect in a solution-processable graphene oxide-donor polymer complex. Appl. Phys. Lett. 2009，95, 253301） 被 Nature Publishing Group-Asia Materials 在2010年4月19日以Graphene composites: On and off為標題突出介紹（HIGHLIGHT）。 原文如下：
NPG Asia Materials research highlight | doi:10.1038/
asiamat.2010.61
Published online 19 April 2010
http://www.natureasia.com/asia-materials/highlight.php?id=649 4/22/2010
Graphene composites: On and off
Graphene is well known for its excellent electronic
properties,but perfection is not always what’s needed.
For example, the ability to control a material’s charge
transport properties through external means is
essential for electronic devices, but
this is difficult to achieve in graphene.
More opportunities for controlling charge transport are
offered by its oxide form, graphene oxide (GO). The
carbonyl and carboxyl groups at the edge of a GO
plane can be functionalized with other molecules, thus
allowing the physical properties of the sheet to be
controlled. A clear example is the recent work by a
joint team of scientists from the National University of
Singapore and East China University of Science and
Technology(Ref.1), who report bistable electrical conductivity
switching in a device based on a graphene oxide–polymer complex.
The team functionalized graphene oxide with poly(N-vinylcarbazole) (PVK) and placed the resulting films
within aluminum and indium–tin oxide contacts. The conductivity of the as-fabricated device, initially relatively low, increased
gradually with the application of a negative-voltage sweep. When a bias of −2 V was reached,
the conductivity jumped up by three orders of
magnitude. This ‘on’ state was maintained during
either negative or positive biased sweeping until a
voltage of +3 V was applied, at which point the
conductivity dropped back to the initial ‘off’ state.
This ‘on–off’ transition process can be repeated several times,
demonstrating that the GO–PVK film could be used as a two-state electronic memory element.
The team used model calculations to explain these
observations, and found that PVK coats the GO
sheets and acts as a tunneling barrier for electrons
moving from one GO sheet to another. When a bias
voltage of−2 V is applied, electrons are injected from
the peripheral molecules of PVK to the central GO
plane, enhancing its conductivity. The process is
perfectly reversible, as the application of a high
enough positive voltage can induce the reverse
transfer of electrons, reducing the conductivity back
to its initial value.
“As it can be processed in solution, GO–PVK provides great opportunities for device fabrication
at low cost and with ease. With the excellent electrical,
mechanical and thermal properties of graphene, this
bistable switching behavior makes GO–PVK a promising alternative or supplement to present
silicon-based semiconductor technology,” says team member
Gang Liu.
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Reference
1. Liu, G.,Zhuang, X., Chen, Y.*, Zhang, B., Zhu, J.,
Zhu, C.-X., Neoh, K.-G. & Kang, E.-T.* Bistable electrical switching and electronic memory
effect in a solution-processable graphene oxide-donor polymer complex. Appl. Phys. Lett. 95, 253301
(2009). | article
Fig. 1: Schematic (left) and photo (right) the
GO-PVK-based device. ITO, indium tin oxide.
