1
8
aromatic hydrazone’s photosensitivity for visible light, the UV-vis
spectrum of SNACA film located at 400–700 nm and the fluorescence
spectrum which exhibited a peak emission at 610 nm, which are all in
the visible area (ESI†). Fig. 5 shows the electro-optical switching
performance of the device at ꢁ2.5 V. For the first 5 s, the device is in
the OFF state in a dark environment where the light intensity is about
ꢁ
2
ꢁ10
1
5 cd m (I ¼ 10 A). The device will switch to the ON state after
ꢁ2
being exposed to light (light intensity is 996 cd m ) for 15 s. The
electro-optical performance of the device was shown to be very stable,
because no obvious change was observed after 100 ON–OFF
switching cycles (ESI†).
In summary, we present for the first time a small organic molecule
suitable for both memory and electro-optical switch applications. The
fabricated devices have promising DRAM behavior, such as a high
9
ON/OFF current ratio (10 ) and long term stability under continuous
stress. Electro-optical switching was demonstrated using the same
device. We envision these types of organic semiconductor will be an
important alternative to the materials traditionally used for memory
and switching applications.
Fig. 4 A) LUMO and HOMO energy levels of the SNACA along with
the work function of the electrode. B) DFT molecular simulation results
(B3LYP/6-311G* level): LUMO, HOMO and molecular electrostatic
potential (ESP) surfaces of the SNACA. C) Linear relationship between
1/2
log (I/V) and V using ITO and Pt as bottom electrode.
Acknowledgements
backbone, indicates that charge carriers can migrate through this
open channel. However, there are some negative electrostatic
potential regions (blue lobes) caused by electron-acceptor groups.
These negative regions can serve as ‘‘traps’’ to impede the mobility of
charge carriers. To clarify how these ‘‘traps’’ could give up the elec-
trons after the electric field disappeared, we studied the conduction
mechanism of the devices at the ‘‘ON’’ state. After the electrical
transition, a linear relationship was observed between log (I/V) and
This work was supported by the Chinese Natural Science Founda-
tion (NSFC 20876101, 21076134), and by the Natural Science
Foundation of Jiangsu Province (BK2010208).
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862 | J. Mater. Chem., 2011, 21, 5860–5862
This journal is ª The Royal Society of Chemistry 2011