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Applications of Graphene-based Composite Materials
Published in Amit Sachdeva, Pramod Kumar Singh, Hee Woo Rhee, Composite Materials, 2021
Gorkem Memisoglu, Burhan Gulbahar, Canan Varlikli
The optical, thermal, mechanical, and electrical properties of composites combining graphene with polymer, quantum dots, or metal oxides can be developed. As an example, indium tin oxide (ITO) is a transparent conductive electrode material widely used in photonics or optoelectronics applications. ITO is more expensive than graphene due to the rare earth element indium in its structure. A graphene-based composite layer is a candidate to take the place of ITO due to its similar work function (4.5 eV), high transparency to light, and high flexibility (Zhang et al. 2006), (Wu et al. 2009), (Kumar and Zhou 2010), (Keersmaecker et al. 2018). It is very important and valuable to develop low-cost, easily prepared, high-quality graphene-based composites to use instead of ITO in organic lighting applications like organic light-emitting diodes (OLEDs) or solar cells and other related applications (Wu et al. 2009), (Chang et al. 2010), (De et al. 2010), (Kumar and Zhou 2010), (Keersmaecker et al. 2018).
Introduction of Graphene
Published in Abhay Kumar Singh, Tien-Chien Jen, Chalcogenide, 2021
Abhay Kumar Singh, Tien-Chien Jen
The difficulty with using ITO films is the expensive scarcity of the Indium cost that is about US$ 1000/kg. Additionally, this element can be finished very quickly. Their preparation methods such as sputtering, evaporation, pulsed laser deposition and electroplating are expensive. By nature, ITO is a brittle, crystalline material that can fracture easily. Therefore, to resolve these ITO problems scientists have looked at alternatives. To overcome the ITO associated problems, graphene can be a potential alternative due to its lightweight, robust, flexible, chemically stable and low cost. In this order, touch screens based on graphene sheets have been already introduced in the market. Specifically, graphene’s mechanical strength and flexibility has made them superior compared to indium tin oxide and graphene films can be deposited from a solution process over a large area. The pyrolyzing camphor method synthesized graphene layered thin films, optical and electrical sheet resistance and transmittance were obtained at 860 S2/sq cm and 91% (at 550 nm wavelength), respectively [124]. Moreover, more than 80% transparency was also achieved in the range of 250 to 1750 nm compared to ITO glass from 250–800 nm.
Strategies for Performance Improvement of Organic Solar Cells
Published in Sam Zhang, Materials for Energy, 2020
The main feature of ITO is its combination of electrical conduction and optical transparency, which can be fabricated over a large area by sputtering method. It has been widely used in transparent conductive electrodes. However, ITO also has some drawbacks, such as the high price of indium, brittleness and lack of flexibility, and the expensive vacuum equipment in the deposition process. Therefore, people are trying to find alternatives for ITO. In OSCs, metal nanostructures have the potential to replace ITO because of their flexibility and absorption enhancement in the near infrared.
Selection rules and a new model for stable topological defect arrays in nematic liquid crystal
Published in Liquid Crystals, 2021
Indium-Tin-Oxide (ITO) is sputtered over the substrate surface. The top ITO is full, and the bottom one is a square or hexagonal pixel array (Figure 2(b)). NLC is vertically aligned on the ITO with Polyimide (PI) coated on the surface. An individual pixel can be a pad, a fishbone or a coil (Figure 2(d)). The fine strips and slits of the electrode are fabricated by wet etching. The width of the strip and the spacing between the strips are 3 . The pixel sizes are 200 200 , 100 100 or 50 50 . The cell gap is 3 .
Wide wavelength range tunable guided-mode resonance filter based on incident angle rotation
Published in Journal of Modern Optics, 2019
Zhibin Ren, Yahui Sun, Kaipeng Zhang, Zihao Lin, Jiasheng Hu
The major fabrication steps include thin-film deposition and lithographic patterning. A layer of ITO with a thickness of 61 nm is first vapor-deposited on the cleaned microscopic glass substrate using a sputtering system. A layer of Si3N4 with a thickness of 55 nm is then vapor-deposited on the ITO waveguide layer. The optical constants and thicknesses of the films are measured using ellipsometry. Thereafter, a positive photoresist layer is spin coated on the Si3N4 layer. After baking the photoresist at 110 °C for 20 min, the 1D grating structure with its period of 251 nm and fill factor of 0.5 is patterned by interference lithography with two UV laser beams, and the groove depth is obtained through exact control of developing time. Figure 5(a) displays the atomic force microscope (AFM) image of the GMRF profile after the development of the photoresist. The results show that the period of the grating sample is 251.84 nm, and the groove depth of the grating is 93.142 nm, and these values are close to the initial designed values in Figure 4(a).
NIOSH’s Respiratory Health Division: 50 years of science and service
Published in Archives of Environmental & Occupational Health, 2018
Kristin J. Cummings, Doug O. Johns, Jacek M. Mazurek, Frank J. Hearl, David N. Weissman
Another example relates to RHD’s work on indium lung disease. Indium-tin oxide (ITO) is a sintered material used in the production of displays, touch screens, solar panels, and architectural glass. In 2009, RHD responded to an HHE request from the management of an ITO production facility where two workers had developed the rare disease pulmonary alveolar proteinosis, subsequently identified as part of a spectrum of disease manifestations related to indium exposure.56,57 RHD found evidence of evolving lung function abnormalities that appeared to be more common in workers with higher indium exposures.58 This HHE led to a multidisciplinary NIOSH research study that characterized the in vivo toxicity and physicochemical properties of production materials,59,60 as well as the quantitative relationship between indium exposure and early biomarkers of indium lung disease.61,62