Molecular doping is an efficient, non-destructive, and simple method for changing the electronic structure of materials. Here, we present a simple air ambient vapor deposition method for functionalization of pristine graphene with a strong electron acceptor: copper chloride. The doped graphene was characterized by Raman spectroscopy, UV-vis-NIR optical absorption spectroscopy, scanning electron microscopy, and electro-physical measurements performed using the 4-probe method. The effect of charge transfer from graphene to a dopant results in shifting the Fermi level in doped graphene. The change of the electronic structure of doped graphene was confirmed by the tangential Raman peak (G-peak) shift and by the appearance of the gap in the UV-vis-NIR spectrum after doping. Moreover, the charge transfer resulted in a substantial decrease in electrical sheet resistance depending on the doping level. At the highest concentration of copper chloride, a Fermi level shift into the valence band up to 0.64 eV and a decrease in the sheet resistance value by 2.36 times were observed (from 888 Ω/sq to 376 Ω/sq for a single graphene layer with 97% of transparency).

1.
Y.
Xu
and
J.
Liu
, “
Graphene as transparent electrodes: Fabrication and new emerging applications
,”
Small
12
,
1400
1419
(
2016
).
2.
M.
Craciun
,
T.
Bointon
, and
S.
Russo
, “
Is graphene a good transparent electrode for photovoltaics and display applications?
,”
IET Circuits Devices Syst.
9
(
6
),
403
412
(
2015
).
3.
P. C.
Zhao
,
Y.
Shon
,
Y.
Yoon
,
I.
Lee
,
C.
Song
,
J.
Lee
, and
H.
Kim
, “
Properties of room-temperature ferromagnetic semiconductor in manganese-doped bilayer graphene by chemical vapor deposition
,”
J. Mater. Chem. C
3
(
17
),
4235
4238
(
2015
).
4.
Y.
Liu
,
N.
Tang
,
X.
Wan
,
Q.
Feng
,
M.
Li
,
Q.
Xu
,
F.
Liu
, and
Y.
Du
, “
Realization of ferromagnetic graphene oxide with high magnetization by doping graphene oxide with nitrogen
,”
Sci. Rep.
3
,
2566
(
2013
).
5.
L.
Qu
,
Y.
Liu
,
J.-B.
Baek
, and
L.
Dai
, “
Nitrogen-doped graphene as efficient metal-free electrocatalyst for oxygen reduction in fuel cells
,”
ACS Nano
4
(
3
),
1321
1326
(
2010
).
6.
Z.
Jin
,
J.
Yao
,
C.
Kittrell
, and
J. M.
Tour
, “
Large-scale growth and characterizations of nitrogen-doped monolayer graphene sheets
,”
ACS Nano
5
(
5
),
4112
4117
(
2011
).
7.
M.
Rybin
,
A.
Pereyaslavtsev
,
T.
Vasilieva
,
V.
Myasnikov
,
I.
Sokolov
,
A.
Pavlova
,
E.
Obraztsova
,
A.
Khomich
,
V.
Ralchenko
, and
E.
Obraztsova
, “
Efficient nitrogen doping of graphene by plasma treatment
,”
Carbon
96
,
196
202
(
2016
).
8.
A.
Pereyaslavtsev
,
M.
Rybin
,
T.
Vasilieva
,
V.
Miasnikov
, and
I.
Sokolov
, “
Experimental study of nitrogen-doped graphene by spectroscopic and probe methods of surface analysis
,”
J. Nanophotonics
10
(
1
),
012521
(
2016
).
9.
S.
Agnoli
and
M.
Favarob
, “
Doping graphene with boron: A review of synthesis methods, physicochemical characterization, and emerging applications
,”
J. Mater. Chem. A
4
,
5002
5025
(
2016
).
10.
F.
Hassani
,
H.
Tavakol
,
F.
Keshavarzipoura
, and
A.
Javaheria
, “
A simple synthesis of sulfur-doped graphene using sulfur powder by chemical vapor deposition
,”
RSC Adv.
6
,
27158
27163
(
2016
).
11.
O.
Leenaerts
,
B.
Partoens
, and
F. M.
Peeters
, “
Adsorption of H2O, NH3, CO, NO2, and NO on graphene: A first-principles study
,”
Phys. Rev. B
77
,
125416
(
2008
).
12.
H.
Liu
,
Y.
Liu
, and
D.
Zhu
, “
Chemical doping of graphene
,”
J. Mater. Chem.
21
,
3335
3345
(
2011
).
13.
A. C.
Crowther
,
A.
Ghassaei
,
N.
Jung
, and
L. E.
Brus
, “
Strong charge-transfer doping of 1 to 10 layer graphene by NO2
,”
ACS Nano
6
,
1865
1875
(
2012
).
14.
S.
Bae
,
H.
Kim
,
Y.
Lee
,
X.
Xu
,
J.-S.
Park
,
Y.
Zheng
,
J.
Balakrishnan
,
T.
Lei
,
H. R.
Kim
,
Y.
Song
 et al, “
Roll-to-roll production of 30-inch graphene films for transparent electrodes
,”
Nat. Nanotechnol.
5
,
574
578
(
2010
).
15.
Y.
Song
,
W.
Fang
,
A.
Hsu
, and
J.
Kong
, “
Iron (III) chloride doping of CVD graphene
,”
Nanotechnology
25
(
39
),
395701
(
2014
).
16.
N. A.
Vinogradov
,
K. A.
Simonov
,
A. V.
Generalov
,
A. S.
Vinogradov
,
D. V.
Vyalikh
,
C.
Laubschat
,
N.
Mårtensson
, and
A. B.
Preobrajenski
, “
Controllable p-doping of graphene on Ir(111) by chlorination with FeCl3
,”
J. Phys.: Condens. Matter
24
(
31
),
314202
(
2012
).
17.
D.
Zhan
,
L.
Sun
,
Z. H.
Ni
,
L.
Liu
,
X. F.
Fan
,
Y.
Wang
,
T.
Yu
,
Y. M.
Lam
,
W.
Huang
, and
Z. X.
Shen
, “
FeCl3-based few-layer graphene intercalation compounds: single linear dispersion electronic band structure and strong charge transfer doping
,”
Adv. Funct. Mater.
20
,
3504
3509
(
2010
).
18.
K. C.
Kwon
,
K. S.
Choi
,
C.
Kim
, and
S. Y.
Kim
, “
Effect of transition-metal chlorides on graphene properties
,”
Phys. Status Solidi A
211
,
1794
1800
(
2014
).
19.
T.
Wehling
,
K.
Novoselov
,
S.
Morozov
,
E.
Vdovin
,
M.
Katsnelson
,
A.
Geim
, and
A.
Lichtenstein
, “
Molecular doping of graphene
,”
Nano Lett.
8
(
1
),
173
177
(
2008
).
20.
D.
Kim
,
D.
Lee
,
Y.
Lee
, and
D. Y.
Jeon
, “
Work-function engineering of graphene anode by bis(trifluoromethanesulfonyl)amide doping for efficient polymer light-emitting diodes
,”
Adv. Funct. Mater.
23
,
5049
5055
(
2013
).
21.
V. I.
Tsebro
,
A. A.
Tonkikh
,
D. V.
Rybkovskiy
,
E. A.
Obraztsova
,
E. I.
Kauppinen
, and
E. D.
Obraztsova
, “
Phonon contribution to electrical resistance of acceptor-doped single-wall carbon nanotubes assembled into transparent films
,”
Phys. Rev. B
94
,
245438
(
2016
).
22.
P. V.
Fedotov
,
V. A.
Eremina
,
A. A.
Tonkikh
,
A. I.
Chernov
, and
E. D.
Obraztsova
, “
Enhanced optical transparency of films formed from sorted metallic or semiconducting single-walled carbon nanotubes filled with CuCl
,”
Phys. Status Solidi B
253
(
12
),
2400
2405
(
2016
).
23.
V. I.
Kleshch
,
A. A.
Tonkikh
,
S. A.
Malykhin
,
E. V.
Redekop
,
A. S.
Orekhov
,
A. L.
Chuvilin
, and
A. N.
Obraztsov
, “
Field emission from single-walled carbon nanotubes modified by annealing and CuCl doping
,”
Appl. Phys. Lett.
109
(
14
),
143112
(
2016
).
24.
G.
Barin
,
Y.
Song
,
I.
Gimenez
,
A.
Filho
,
L.
Barreto
, and
J.
Kong
, “
Optimized graphene transfer: Influence of polymethylmethacrylate (PMMA) layer concentration and baking time on grapheme final performance
,”
Carbon
84(C)
,
82
90
(
2015
).
25.
A.
Das
,
S.
Pisana
,
B.
Chakraborty
,
S.
Piscanec
,
S. K.
Saha
,
U. V.
Waghmare
,
K. S.
Novoselov
,
H. R.
Krishnamurthy
,
A. K.
Geim
,
A. C.
Ferrari
 et al, “
Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor
,”
Nat. Nanotechnol.
3
,
210
215
(
2008
).
You do not currently have access to this content.