Sigmaaldrich offers a number of graphene oxide products. Using insitu kelvin probe force microscopy kpfm to measure surface potential, we investigated the timedependent work function evolution of solutionprocessed graphene oxide go under ultraviolet uv irradiation. The graphene layers were functionalized by aminebased groups using a simple spincoating method. Tuning the work function of silver by deposition of. The representative structure of graphene oxide nanoflakes. The present invention relates to graphene having an increased work function including graphene and transition metal dopants containing at least one of iridium, molybdenum, osmium, rhodium, gold, and palladium doped on the graphene surface. Tuning of graphene work function by alkyl chain length in. Nguyen1,b 1semiconductor and dimensional metrology.
At the beginning of graphene history go was only a simple and cheap step for preparation of single and multilayer graphene films and bulk structures by reduction. Oxidative stressmediated antibacterial activity of. Work function tuning of reduced graphene oxide thin films. The titanium dioxide tio 2 nanoparticles are formed at the same time as the graphene oxide go is reduced to graphene. Graphene oxide go layers are the individual sheets of conventional graphite oxide cgo synthesized from graphene. Work function tuning in twodimensional mos 2 fieldeffect. Work function tunability of graphene with thermally. In this work, the work function of graphene doped by different metallic dopants and different concentrations has been studied using dft.
Semiordered so, top and random r, bottom models of graphene oxide generated and studied as part of this work. It has also been identified as one of the most promising materials for postsilicon electronics. Hydrazinereduction of graphite and graphene oxide sungjin park a,b, jinho an a, jeffrey r. Grossman department of materials scienceand engineering, massachusettsinstituteof technology, 77massa chusetts avenue, cambridge massachusetts 029 4307, united states reduced graphene oxide rgo is. Graphene flakes in the active layer of bulk heterojunction. Structure and chemistry of graphene oxide in liquid water. For many such applications, modulation of the electrical and optical properties, together with tuning the band gap and the resulting work function of zero band gap graphene are. Ruoff a, a department of mechanical engineering and the texas materials institute, the university of texas at austin, one university station c2200, austin, tx 787120292, usa b department of chemistry, inha university, incheon 402751, republic. Study of organic pollutant removal capacity and work. Todays graphene is normally produced using mechanical or thermal exfoliation, chemical vapour deposition cvd, and epitaxial growth. The wet chemical method based on oxidation of natural graphite to graphite oxide go followed by exfoliation to graphene oxide, and finally. Determination of graphene work function and graphene. Reduced graphene oxide rgo is a promising material for a variety of thinfilm optoelectronic applications. Graphene oxide go has shown great potential as a component in various devices due to its excellent solution processability and.
Work function engineering of graphene article pdf available in nanomaterials 42. In this work, the work function wf of graphenes, which are used as electronic devices, has been designed and evaluated by using the firstprinciple approach. Direct measurement of dirac point energy at the graphene. The further studies revealed the substantial structure imperfection of graphene oxide. Different states of graphene were considered, such as surface modification, doping, and defects. S braithwaite2 and satheesh krishnamurthy1, 1school of engineering and innovation, the open university, milton keynes, mk7 6aa, uk 2school of physical sciences, the open university, milton keynes, mk7 6aa, uk. Contact organic transistors boseok kang department of chemical engineering, pohang university of science and technology, pohang, 790784 korea. Graphene, which shows potential as an alternative to conventional conductive transparent metal oxides, may play a central role. Read improving the efficiency of organic photovoltaics by tuning the work function of graphene oxide hole transporting layers, nanoscale on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Unlike a standard bare tether equipped with an active electron emitter, lwts close the electrical circuit cathodic contact with the ambient plasma in a passive manner thanks to the thermionic and photoelectric effects.
Stress dependence of the suspended graphene work function. Design and adjustment of the graphene work function via. For this purpose the following gaussian probability density distribution function pdf is used. Combined effects of functional groups, lattice defects. We found that the work function of go exposed in uv shows a notable decrease with increasing irradiation time, which is proposed to be attributed to the gradual disappearance of. The adsorption of different concentrations on metal adatoms on graphene is also studied. Pdf work function tuning of graphene oxide by using cesium. With a crau or ni contact, the work function of graphene is pinned to that of the contacted metal, whereas with a pd or au contact the work function assumes a value of. Go has oxidative defects which break the perfect strucutre of graphene. The ultraviolet photoelectron spectroscopic analysis revealed that the work function decreased from 5.
Potts a, aruna velamakanni a, shanthi murali a, rodney s. Work function modulation and thermal stability of reduced. The impact of functionalization article on the stability. Having unique properties, graphene layers are a quite interesting nanomaterial for industrial applications. Pdf work function engineering of graphene researchgate. The 281 features characterizing the oxygen distribution capture the differences between nanoflakes with similar graphene primary structures and oxygen concentrations, but different patterning of oxygen groups on the surface. The triethanolamine tea used in the process has two roles. The aminebased compounds were composed of phenyl amine and methyl, ethyl, propyl, nt.
Tuned reduced graphene oxide via direct surface functionalization as sourcedrain electrodes in bottom. This tuning is accomplished in order to minimize the sheet resistance of graphene or graphene oxide films and to match the work function of these derivatives with the homo and lumo level of many. The deposited oxide does not induce any defects in the high. Hightwalker,1 xuelei liang,3 alan seabaugh,2 debdeep jena,2 huili grace xing,2 david j. It acts as a reducing agent for the go as well as capping. Work function tuning of graphene oxide by using cesium applied to. Sizedependent work function and catalytic performance of. The work function for this 3 layer mgo on ag100 is therefore 2.
The effective utilization of workfunction wf tuned solution processable graphenebased derivatives as both hole and electron transport layers in organic photovoltaic opv devices is demonstrated. Direct correlation between work function and oxygen. Supporting information engineering work function of graphene oxide from p to n type using a low power atmospheric pressure plasma jet avishek dey 1, paheli ghosh1, james bowen1, n. This is why go is especially fit for use in the production of transparent conductive films, like the ones used for flexible electronics, solar cells, chemical sensors and more. This element is unique in that its unique electronic structure allows for hybridization to build up sp3,sp2, and sp networks and, hence, to form more known stable allotropes than any. For example in the case of cs doping, the work function saturates at 2. Since the first report on mechanical exfoliation of monolayer graphene in 2004, interest in graphite oxide which is produced by. Graphene oxide go is useful and promising material for graphene based applications in electronic, optics, chemistry, energy storage, and biology.
We investigated the sizedependent work function and catalytic performance of gold nanoparticles aunps decorated graphene oxide go. This work presents experimental results on a novel. Engineering work function of graphene oxide from p to n. The impact of functionalization on the stability, work. Oxidative stressmediated antibacterial activity of graphene oxide and reduced graphene oxide in pseudomonas aeruginosa sangiliyandi gurunathan, jae woong han, ahmed abdal dayem, vasuki eppakayala, jinhoi kimdepartment of animal biotechnology, konkuk university, seoul, south koreabackground. The obtained graphene sealed microchambers can support large pressure differences, providing controllable stretching of the nearly impermeable graphene membranes.
Determination of graphene work function and grapheneinsulatorsemiconductor band alignment by internal photoemission spectroscopy rusen yan,1,2,a qin zhang,1,2 wei li,1,3 irene calizo,1 tian shen,1,4 curt a. Graphene holds great promise for potential use in nextgeneration electronic and. Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. Extended graphene oxide models were simulated using an orthorhombic cell with a 7. In this work, we demonstrate doping graphene oxide go films using a low power atmospheric pressure plasma jet appj with subsequent tuning of the work function. Low work function tethers lwt is long conductors with a segment coated with a material that has looselybounded electrons. In general, such methods involve chemical oxidation of natural graphite using various solutionbased routes to synthesize hydrophilic graphite oxide followed by. N1s xps analysis of the bonding configurations of n atoms in reduced graphene oxide. Impact of gate workfunction on memory characteristics in.
Work function engineering of graphene cyberleninka. Graphene having an increased function according to the present invention has a higher work function than conventional graphene, and can be used in. Graphene oxide films can be deposited on essentially any substrate, and later converted into a conductor. The present invention relates to graphene having reduced work function comprising graphene and an alkali metal ion dopant doped to the graphene surface. We report on work function measurements on graphene, which is exfoliated over a predefined array of wells in silicon oxide, by kelvin probe force microscopy operating in a vacuum. The systematic tuning of the functionalized graphene oxide go wf took place by. Impact of gate workfunction on memory characteristics in al 2o 3hfo xal 2o 3 graphene chargetrap memory devices sejoon lee,1,2,a emil b.
Kr101479217b1 decrease of work function using doped. Firstly, wf strongly depends on the width of pristine graphene. Work function wf tuning of the contact electrodes is a key requirement in several device technologies, including organic photovoltaics opvs, organic lightemitting diodes oleds, and complementary metal oxide semiconductor cmos transistors. In contrast to the high work function of exposed graphene of 4. Work function tuning of reduced graphene oxide thin films the. Consequently, it has generated unprecedented excitement in the scientific community. Tuning the work function of graphene toward application as. However, the generation of graphene layers from graphite is quite expensive, but can be achieved at lower cost via controlled oxidation of graphite. Work function tuning in twodimensional mos 2 fieldeffecttransistors with graphene and titanium sourcedrain contacts. Journal of materials chemistry a royal society of chemistry. S2 work functions of a undoped rgo and b nitrogen doped nrgo determined by.
Two main barriers to its widespread use are the lack of 1 fabrication protocols leading to tailored functionalization of the graphene sheet with oxygencontaining chemical groups, and 2 understanding of the impact of such functional groups on the stability and on the. Reduced work function of graphene by metal adatoms. Graphene oxide go is a material in whichthe fermi level can be manipulated with reductia on procedure. The graphene was synthesized by the chemical vapor deposition method. In this study, the effect of alkyl chain length in aminebased compounds on the work function of graphene was investigated. In graphene based electronic devices, the graphene work function is one of the most important properties that should be taken into considerations. Two main barriers to its widespread use are the lack of 1. The effect of go on both work function and r6g dye removal capacity of magnetite nanoparticles fe 3 o 4 nps has been studied. Direct correlation between work function and oxygen concentration of graphene oxide reduced graphene oxide films on ito lamprini sygellou1, georgios paterakis1, dimitrios tasis1,2 and costas galiotis1,3 1foundation of research and technology hellas, institute of chemical engineering and high temperature chemical processes forthiceht, p. Since graphenes having reduced functions according to the present invention have lower work function values than conventional graphenes, they can be easily used as electron transport materials for electronic devices such as leds and oleds. The maximally oxidized bulk product is a yellow solid with c.
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