TY - JOUR
T1 - Improvement of transparent conducting nanotube films by addition of small quantities of graphene
AU - King, Paul J.
AU - Khan, Umar
AU - Lotya, Mustafa
AU - De, Sukanta
AU - Coleman, Jonathan N.
PY - 2010/7/27
Y1 - 2010/7/27
N2 - We demonstrate a water-based method to prepare transparent, conducting graphene/single-walled nanotube hybrid films. While the transmittance decreases slightly with increasing graphene content, the DC conductivity, σDC, and sheet resistance scale non-monotonically with film composition. We observe an optimum composition of ∼3 wt % graphene, which results in a peak in the DC conductivity. We have calculated the figure of merit, the DC to optical conductivity ratio, σDC/ σOp, which also shows a peak at this composition. We find that this effect is only present for small graphene flakes. In addition, acid treatment increases both the σDC and σDC/ σOp by × - 2.5. Interestingly, acid treatment is more effective for films close to the optimum composition. This has the effect of sharpening the peaks in both σDC and σDC/ σOp. For acid-treated films, addition of 3 wt % graphene results in a 40% increase in σDC/σOp compared to the nanotube-only film, from 12.5 to 18. Optimized, acid-treated films display transmittance of 80% coupled with a sheet resistance of 100 Ω/□.
AB - We demonstrate a water-based method to prepare transparent, conducting graphene/single-walled nanotube hybrid films. While the transmittance decreases slightly with increasing graphene content, the DC conductivity, σDC, and sheet resistance scale non-monotonically with film composition. We observe an optimum composition of ∼3 wt % graphene, which results in a peak in the DC conductivity. We have calculated the figure of merit, the DC to optical conductivity ratio, σDC/ σOp, which also shows a peak at this composition. We find that this effect is only present for small graphene flakes. In addition, acid treatment increases both the σDC and σDC/ σOp by × - 2.5. Interestingly, acid treatment is more effective for films close to the optimum composition. This has the effect of sharpening the peaks in both σDC and σDC/ σOp. For acid-treated films, addition of 3 wt % graphene results in a 40% increase in σDC/σOp compared to the nanotube-only film, from 12.5 to 18. Optimized, acid-treated films display transmittance of 80% coupled with a sheet resistance of 100 Ω/□.
KW - graphene
KW - hybrid
KW - nanotube
KW - resistance
KW - transmittance
KW - transparent conductor
UR - http://www.scopus.com/inward/record.url?scp=77955529593&partnerID=8YFLogxK
U2 - 10.1021/nn100542z
DO - 10.1021/nn100542z
M3 - Article
AN - SCOPUS:77955529593
SN - 1936-0851
VL - 4
SP - 4238
EP - 4246
JO - ACS Nano
JF - ACS Nano
IS - 7
ER -