Reduced graphene oxide: an introduction - Page 6

Graphene 3D Lab has announced a new class of graphene materials with exceptional oil absorbance properties. The Company has commissioned a new production reactor that results in a 5-fold increase in the production capabilities of Graphene Oxide and Reduced Graphene Oxide; Using this extended capacity, the Company produced a new class of materials: Graphene Oxide and Reduced Graphene Oxide Foams. These foams are in the class of ultralight materials and have density of approximately 20 mg/cm 3 , which is only about 17 times heavier than air.

These new materials are able to hold up to 3,500%-8,000% of their own weight of organic solvents and oils, all while being unaffected by water. This attribute could be significant in minimizing the damage caused by oil spills. Due to its high oil absorption capacity, these porous solid state foams are an excellent solution for fast and effective oil clean-up. In addition, they may also have commercial application in energy storage devices, chemical catalysts and ultrasensitive sensors.

Graphene 3D Lab has announced the commencement of a new production reactor that results in a 5-fold increase of production capabilities of Graphene Oxide and Reduced Graphene Oxide.

According to G3L, the necessity of expanding production volume for these materials is driven by increased demand as well as by the internal consumption of the Company's Industrial Materials division. G3L stated that it is committed to staying on track to satisfy the increasing materials demand. said

Researchers at the University of California at Berkeley and the Lawrence Berkeley National Laboratory have developed a new solution-based, cost-effective way to wrap reduced graphene oxide around the surface of ultrathin transparent conducting copper nanowires. The technique aims to significantly improve the stability of the wires in air and reduce the amount of light scattered by the materials.

Thin films made of the wires might be used in optoelectronics devices, particularly in displays and flexible electronics. Metal nanowire films could make good replacements for the expensive and brittle indium tin oxide (ITO) in next-generation electronics, thanks to their excellent electrical and optical properties and the fact that they can be easily processed in solution.

An international team of researchers conducted a study that suggests that dental fillings made of graphene oxide could be much more durable than those based on metals or ceramic materials.

Graphene offers both exceptional strength and resistance against corrosion, which could greatly improve current fillings that tend to corrode or break. The researchers attempted to add graphene into dental materials, in order to increase their resistance to corrosion as well as to improve their mechanical properties.

A team of researchers from the Indian Institute of Science (IISc) has developed a graphene oxides-based sensor that can detect nitrogen dioxide (NO2) in the atmosphere. The sensor can detect as little as a single NO2 molecule among millions of other molecules and it works even at room temperatures, unlike other common nitrogen sensors that are known to be high temperature devices.

For the development of this sensor, the team used fibre bragg grating, an optical fibre similar to the ones used for communication purposes. However, it can reflect one particular wavelength of light and transmit others. The IISc team covered the fibre bragg grating with an ultra thin layer of reduced graphene oxide and developed the sensor. by modifying the optical fibre, the scientists were able to use it in different applications like gas sensing and bio-sensing.

A team of researchers at the Indian Institute of Science Education and Research presents a promising anode material for lithium-ion batteries, by incorporating unique 3D cobalt oxide microstructures into a reduced graphene oxide composite.

Metal oxides present a potential alternative to conventional graphite anodes and Li alloys. Cobalt oxide (CoO) has particularly promising properties, namely a high specific capacity and excellent cycling stability against lithium. However, particle aggregation and volume expansion have thus far restricted its candidacy as an appropriate anode material. Merging CoO into a graphene hydrogel, which acts as a mechanically stable 3D support, the researchers eliminate the problem of volume expansion. Furthermore, the completely interconnected hybrid material presents improved conductivity.

Researchers at Swinburne University of Technology, collaborating with Monash University, have developed an ultrathin, flat, lightweight graphene oxide optical lens with extraordinary flexibility, that enables potential applications in on-chip nanophotonics and improves the conversion process of solar cells. It might also open up new possibilities in areas like non-invasive 3D biomedical imaging, aerospace photonics, micromachines and more.

Recent developments in nano-optics and on-chip photonic systems have increased the demand for ultrathin flat lenses with 3D subwavelength focusing capability (the ability to see details of an object smaller than 200 nanometres). A number of ultrathin flat lens concepts have been developed, but their real-life application is limited due to their complex design, narrow operational bandwidth and time consuming manufacturing processes. This lens, however, has a 3D subwavelength capability that is 30 times more efficient, able to tightly focus broadband light from the visible to the near infrared, and offers a simple and low-cost manufacturing method.

Researchers from Tsinghua University in Beijing demonstrated a graphene-based LED that not only can be tuned to emit different colors of light, but can do so across nearly the entire visible spectrum: from blue (450-nm wavelength) to red (750-nm wavelength)—basically all colors but the darkest blues and violets. Such a color tunable LED has never before been realized.

The scientists made the light-emitting material from the interface of two different forms of graphene. These forms are graphene oxide (GO) and reduced graphene oxide (rGO). Placed at the interface of the GO and rGO is a special type of partially reduced GO that has optical, physical, and chemical properties that lie somewhere in between those of GO and rGO. The most important "blended" property of the interfacial layer is that it has a series of discrete energy levels, which ultimately allows for the emission of light at many different energies, or colors.

Researchers from the University of Maryland found that intercalating (embedding) sodium ions in a reduced graphene oxide (rGO) network, printed with graphene oxide (GO) ink, can significantly improve its performance as a transparent conductor in displays, solar cells and electronic devices.

The scientists used cost-effective materials and production techniques to receive a highly scalable printed electronics system that produces relatively inexpensive and stable conductors. The team theorizes the increased stability is due to the natural oxidation of sodium along the edges of the printed networks which forms a barrier that prevents ion loss. Networks printed with the ink exhibit up to 79 percent optical transmittance and 311 Ohms per square of sheet resistance.

Nokia recently issued a patent for a graphene oxide-based sensor for protection of mobile devices against water damages. The sensor will use a graphene oxide sensing film senses moisture content or change in relative humidity and triggers an ultra-fast disconnection of the mobile device from its power source (battery).

The sensor will include a sensor capable of sensing water in liquid or vapor form based on the measurement of large time derivative values. The sensor will comprise of a graphene oxide thin film and two or more electrodes in contact with the thin film. An electronic switch will be connected to the sensor and to a power source that powers the circuitry in the electronic device. The GO can be easily integrated into the sensor as a thin film by printing it on the power source's surface.The film should be less than 100 nanometers thick and could also be spray-coated or spin-coated onto the surface.