<s>
A	O
unimolecular	B-Algorithm
rectifier	I-Algorithm
is	O
a	O
single	O
organic	O
molecule	O
which	O
functions	O
as	O
a	O
rectifier	B-Algorithm
(	O
one-way	O
conductor	O
)	O
of	O
electric	O
current	O
.	O
</s>
<s>
Their	O
publication	O
was	O
the	O
first	O
serious	O
and	O
concrete	O
theoretical	O
proposal	O
in	O
the	O
new	O
field	O
of	O
molecular	B-Algorithm
electronics	I-Algorithm
(	O
UE	O
)	O
.	O
</s>
<s>
Based	O
on	O
the	O
mesomeric	O
effect	O
of	O
certain	O
chemical	O
compounds	O
on	O
organic	O
molecules	O
,	O
a	O
molecular	O
rectifier	B-Algorithm
was	O
built	O
by	O
simulating	O
the	O
pn	O
junction	O
with	O
the	O
help	O
of	O
chemical	O
compounds	O
.	O
</s>
<s>
This	O
proposal	O
was	O
verified	O
in	O
two	O
papers	O
in	O
1990	O
and	O
1993	O
by	O
the	O
groups	O
of	O
John	O
Roy	O
Sambles	O
(	O
University	O
of	O
Exeter	O
,	O
UK	O
)	O
and	O
Geoffrey	O
Joseph	O
Ashwell	O
(	O
Cranfield	O
University	O
now	O
at	O
the	O
Lancaster	O
University	O
,	O
UK	O
)	O
,	O
using	O
a	O
monolayer	O
of	O
hexadecylquinolinium	O
tricyanoquinodimethanide	O
sandwiched	O
between	O
dissimilar	O
metal	O
electrodes	O
(	O
magnesium	O
and	O
platinum	B-Operating_System
)	O
and	O
then	O
confirmed	O
in	O
three	O
papers	O
in	O
1997	O
and	O
2001	O
by	O
Metzger	O
(	O
now	O
at	O
the	O
University	O
of	O
Alabama	O
)	O
and	O
coworkers	O
,	O
who	O
used	O
identical	O
metals	O
(	O
first	O
aluminium	O
,	O
then	O
gold	O
)	O
.	O
</s>
<s>
About	O
nine	O
similar	O
rectifiers	B-Algorithm
of	O
vastly	O
different	O
structure	O
have	O
been	O
found	O
by	O
Metzger	O
's	O
group	O
between	O
1997	O
and	O
2006	O
.	O
</s>
<s>
Some	O
more	O
perylene	O
based	O
organic	O
rectifiers	B-Algorithm
with	O
PEG	O
(	O
polyethylene	O
glycol	O
)	O
swallowtails	O
have	O
been	O
synthesized	O
in	O
Mattern	O
's	O
lab	O
by	O
Ramakrishna	O
Samudrala	O
.	O
</s>
<s>
These	O
rectifiers	B-Algorithm
would	O
allow	O
the	O
rectification	O
to	O
be	O
measured	O
with	O
flexibility	O
.	O
</s>
<s>
Single	O
molecules	O
bonded	O
covalently	O
to	O
gold	O
have	O
been	O
studied	O
by	O
scanning	O
tunneling	O
spectroscopy	O
and	O
some	O
of	O
them	O
are	O
unimolecular	B-Algorithm
rectifiers	I-Algorithm
,	O
studied	O
as	O
single	O
molecules	O
,	O
as	O
shown	O
by	O
the	O
groups	O
of	O
Luping	O
Yu	O
(	O
University	O
of	O
Chicago	O
)	O
and	O
Ashwell	O
(	O
later	O
at	O
Lancaster	O
University	O
,	O
UK	O
)	O
.	O
</s>
