Fabrication and Evaluation of Solution-Processed Reduced Graphene Oxide Electrodes for p- and n-Channel Bottom-Contact Organic Thin-Film Transistors

Becerril, Héctor A.; Stoltenberg, Randall M.; Tang, Ming Lee; Roberts, Mark; Liu, Zunfeng; Chen, Yongsheng; Kim, Do Hwan; Lee, Bang Lin; Lee, Sang Yoon; Bao, Zhenan

doi:10.1021/nn101369j

Cited by 70 publications

(56 citation statements)

References 59 publications

(119 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The work function of Pd is 5.1 eV which is close to the highest occupied molecular orbital (HOMO) level of pentacene (5.0 eV). On the other hand, the typical work function of highly reduced RGO is reported to be in the range of 4.6-5.0 eV, 12,13,16,24 close to the work function of conventional metal electrodes. Recently, Kumar et al 23 reported that the work function of RGO can be further tuned up to $7 eV by varying the degree of reduction (lower reduction has a higher work function).…”

mentioning

confidence: 64%

“…In order to address the challenge of low charge injection, reduced graphene oxide (RGO) has been introduced as a promising electrode for OFETs due to its high work function and strong p-p interaction with organic molecules which can reduce the injection barrier at the electrode/organic interface. [11][12][13][14][15][16] In addition, its solution-processing method to produce graphene sheets in large quantities at low cost and compatibility with various substrates including plastics, makes them attractive for fabrication of OFETs. It has been shown that RGO consists of sp 2 graphene domains surrounded by a continuous matrix of sp 3 networks, which contains oxygen functional groups such as hydroxyl, epoxy, and carboxyl.…”

mentioning

confidence: 99%

See 1 more Smart Citation

The impact of carbon sp2 fraction of reduced graphene oxide on the performance of reduced graphene oxide contacted organic transistors

Kang

Khondaker

2014

Applied Physics Letters

View full text Add to dashboard Cite

One of the major bottlenecks in fabricating high performance organic field effect transistors (OFETs) is a large interfacial contact barrier between metal electrodes and organic semiconductors (OSCs) which makes the charge injection inefficient. Recently, reduced graphene oxide (RGO) has been suggested as an alternative electrode material for OFETs. RGO has tunable electronic properties and its conductivity can be varied by several orders of magnitude by varying the carbon sp2 fraction. However, whether the sp2 fraction of RGO in the electrode affects the performance of the fabricated OFETs is yet to be investigated. In this study, we demonstrate that the performance of OFETs with pentacene as OSC and RGO as electrode can be continuously improved by increasing the carbon sp2 fraction of RGO. When compared to control palladium electrodes, the mobility of the OFETs shows an improvement of ∼200% for 61% sp2 fraction RGO, which further improves to ∼500% for 80% RGO electrode. Similar improvements were also observed in current on-off ratio, on-current, and transconductance. Our study suggests that, in addition to π-π interaction at RGO/pentacene interface, the tunable electronic properties of RGO electrode have a significant role in OFETs performance.

show abstract

mentioning

confidence: 64%

mentioning

confidence: 99%

The impact of carbon sp2 fraction of reduced graphene oxide on the performance of reduced graphene oxide contacted organic transistors

Kang

Khondaker

2014

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…Although the exact mechanism for the phenomenon is not clear, a possible mechanism is provided here. From a previous report, [ 20 ] we know that an carbon-based electrode (such as RGO) is electron-donating and an organic semiconductor (such as P3HT) is electron-accepting relative to the electrode (similar to a built-in fi eld effect, see f Figure S6a, Supporting Information). Such RGO/organic interfaces have been shown to have low contact resistance and enhanced charge transport, [ 21 ] which may account for the current enhancement in our device.…”

Section: Electrical Assembly and Reduction Of Graphene Oxide In A Sinmentioning

confidence: 95%

Electrical Assembly and Reduction of Graphene Oxide in a Single Solution Step for Use in Flexible Sensors

Guo

Liu

et al. 2011

Advanced Materials

View full text Add to dashboard Cite

“…The typical 5 µm BC transistor gives a mobility of 0.15 cm 2 V −1 s −1 , and the maximum mobility is about 0.33 cm 2 V −1 s −1 , while such value is already one order higher than the transistors without the inducing layer (0.01-0.05 cm 2 V −1 s −1 ), and are comparable to many BC pentacene transistors reported in the literatures. [19,31] A slight nonlinear phenomenon in the low V D observed from the output characteristics indicated the contact issue still existed. With channel length of 10 µm, the maximum mobility increases to 0.78 cm 2 Figure S1, Supporting Information), and the maximum mobility is one of the best among most of the reported BC transistors based on pentacene.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

High‐Performance Bottom‐Contact Organic Thin‐Film Transistors by Improving the Lateral Contact

Zhang

Wang

Zhou

et al. 2017

Adv Elect Materials

View full text Add to dashboard Cite

prepatterned electrodes on the substrates generate artificial steps that significantly affect the morphological uniformity and continuity of the organic active layer at the electrode/organic interfaces, causing large contact resistance. The most common solution is to modify the electrodes, e.g., chemical bonding of thiols on gold, inserting buffer layer on the electrodes, or applying conductive materials such as graphene, polypyrrole as electrodes. [2,10, These approaches could either realize a good energy level alignment or improve the interface morphology to decrease the contact resistance. Nevertheless, the performances of the BC transistors are still insufficient to match the application requirements.It is known that the resistance of the transistors consists of channel resistance and contact resistance. The latter is determined by the carrier injection from the interfaces of the organic/electrode: the top injection and the side injection. [22] With regard to the side injection, a major issue is the morphology discontinuity near the edge of the electrodes. Previously, Kudo and co-workers proposed a method that embedding electrodes into the dielectric layer to achieve a planar interface and obtained a mobility ≈0.48 cm 2 V −1 s −1 (in saturate regime) for pentacene, but this will induce relatively complicate patterning process. [33][34][35] Li et al. treated the electrodes with fluorine substituted benzene thiol and effectively improved the texture from the contacts extending to thwe channel, as well as the performance of corresponding solution casted BC transistors. [30,36,37] Here, we report a simple method to improve the continuity of organic films at the lateral interfaces of electrode/organic through incorporating an organic inducing layer. Inserting an inducing layer has been widely applied in top contact transistors and received considerable attentions. [38][39][40] Herein, the organic layer which forms lamellar grains from the edge of the photolithographypatterned electrodes was deposited prior to depositing the active layer. The following organic semiconductor layer grown on the inducing layer formed lamellar films on the inducing layer, enabling a good contact between the electrodes and the organic semiconductor thin films. As a result, a remarkable decrement of the contact resistance is achieved. Together with the improved film ordering by weak epitaxy on the inducing layer in the channel area, we achieved high performance bottom contact thin film transistors with the maximum mobility exceeding 1 cm 2 V −1 s −1 for pentacene in ambient condition, which is comparable to the top contact ones.One of the main challenges to achieve high-performance bottom-contact transistors involves the organic/electrodes contacts. This study provides a simple approach to address the contact issue by incorporating an inducing layer prior to the organic semiconductor deposition. The molecules of the inducing layer nucleate into lamellar grains from the edge to the channel, resulting in a good morphological contact to th...

show abstract

Fabrication and Evaluation of Solution-Processed Reduced Graphene Oxide Electrodes for p- and n-Channel Bottom-Contact Organic Thin-Film Transistors

Cited by 70 publications

References 59 publications

The impact of carbon sp2 fraction of reduced graphene oxide on the performance of reduced graphene oxide contacted organic transistors

The impact of carbon sp2 fraction of reduced graphene oxide on the performance of reduced graphene oxide contacted organic transistors

Electrical Assembly and Reduction of Graphene Oxide in a Single Solution Step for Use in Flexible Sensors

High‐Performance Bottom‐Contact Organic Thin‐Film Transistors by Improving the Lateral Contact

Contact Info

Product

Resources

About