PMID- 25668323
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20150519
LR  - 20150324
IS  - 1936-086X (Electronic)
IS  - 1936-0851 (Linking)
VI  - 9
IP  - 3
DP  - 2015 Mar 24
TI  - Direct imaging of charge transport in progressively reduced graphene oxide using 
      electrostatic force microscopy.
PG  - 2981-8
LID - 10.1021/nn507150q [doi]
AB  - Graphene oxide (GO) has emerged as a multifunctional material that can be 
      synthesized in bulk quantities and can be solution processed to form large-area 
      atomic layered photoactive, flexible thin films for optoelectronic devices. This 
      is largely due to the potential ability to tune electrical and optical properties 
      of GO using functional groups. For the successful application of GO, it is key to 
      understand the evolution of its optoelectronic properties as the GO undergoes a 
      phase transition from its insulating and optically active state to the 
      electrically conducting state with progressive reduction. In this paper, we use a 
      combination of electrostatic force microscopy (EFM) and optical spectroscopy to 
      monitor the emergence of the optoelectronic properties of GO with progressive 
      reduction. EFM measurements enable, for the first time, direct visualization of 
      charge propagation along the conducting pathways that emerge on progressively 
      reduced graphene oxide (rGO) and demonstrate that with the increasing degree of 
      reduction, injected charges can rapidly migrate over a distance of several 
      micrometers, irrespective of their polarities. Direct imaging reveals the 
      presence of an insurmountable potential barrier between reduced GO (rGO) and GO, 
      which plays the decisive role in the charge transport. We complement charge 
      imaging with theoretical modeling using quantum chemistry calculations that 
      further demonstrate that the role of barrier in regulating the charge transport. 
      Furthermore, by correlating the EFM measurements with photoluminescence imaging 
      and electrical conductivity studies, we identify a bifunctional state in GO, 
      where the optical properties are preserved along with good electrical 
      conductivity, providing design principles for the development of GO-based, 
      low-cost, thin-film optoelectronic applications.
FAU - Yalcin, Sibel Ebru
AU  - Yalcin SE
AD  - daggerCenter for Integrated Nanotechnologies, Materials Physics and Applications 
      Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United 
      States.
FAU - Galande, Charudatta
AU  - Galande C
FAU - Kappera, Rajesh
AU  - Kappera R
FAU - Yamaguchi, Hisato
AU  - Yamaguchi H
AD  -  perpendicularMPA-11 Materials Synthesis and Integrated Devices, Materials Physics and 
      Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 
      87545, United States.
FAU - Martinez, Ulises
AU  - Martinez U
AD  -  perpendicularMPA-11 Materials Synthesis and Integrated Devices, Materials Physics and 
      Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 
      87545, United States.
FAU - Velizhanin, Kirill A
AU  - Velizhanin KA
AD  -  parallelT-1 Physics and Chemistry of Materials, Theoretical Division, Los Alamos 
      National Laboratory, Los Alamos, New Mexico 87545, United States.
FAU - Doorn, Stephen K
AU  - Doorn SK
AD  - daggerCenter for Integrated Nanotechnologies, Materials Physics and Applications 
      Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United 
      States.
FAU - Dattelbaum, Andrew M
AU  - Dattelbaum AM
AD  -  perpendicularMPA-11 Materials Synthesis and Integrated Devices, Materials Physics and 
      Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 
      87545, United States.
FAU - Chhowalla, Manish
AU  - Chhowalla M
FAU - Ajayan, Pulickel M
AU  - Ajayan PM
FAU - Gupta, Gautam
AU  - Gupta G
AD  -  perpendicularMPA-11 Materials Synthesis and Integrated Devices, Materials Physics and 
      Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 
      87545, United States.
FAU - Mohite, Aditya D
AU  - Mohite AD
AD  -  perpendicularMPA-11 Materials Synthesis and Integrated Devices, Materials Physics and 
      Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 
      87545, United States.
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20150213
PL  - United States
TA  - ACS Nano
JT  - ACS nano
JID - 101313589
OTO - NOTNLM
OT  - charge injection
OT  - charge transport
OT  - electrostatic force microscopy (EFM)
OT  - photoluminescence
OT  - progressively reduced graphene oxide
OT  - tight-binding calculations
EDAT- 2015/02/11 06:00
MHDA- 2015/02/11 06:01
CRDT- 2015/02/11 06:00
PHST- 2015/02/11 06:00 [entrez]
PHST- 2015/02/11 06:00 [pubmed]
PHST- 2015/02/11 06:01 [medline]
AID - 10.1021/nn507150q [doi]
PST - ppublish
SO  - ACS Nano. 2015 Mar 24;9(3):2981-8. doi: 10.1021/nn507150q. Epub 2015 Feb 13.