Graphene Quantum Dots: Introduction and Market News - Page 3

ICFO researchers have recently demonstrated a new class of graphene-based flexible and transparent wearable devices that are conformable to the skin and can provide continuous and accurate measurements of multiple human vital signs.

These devices can measure heart rate, respiration rate and blood pulse oxygenation, as well as exposure to UV radiation from the sun. While the device measures the different parameters, the read-out is visualized and stored on a mobile phone interface connected to the wearable via Bluetooth. In addition, the device can operate battery-free since it is charged wirelessly through the phone.

A team of researchers from the Physics, Medicine and Chemistry departments at Heinrich Heine University Düsseldorf (HHU) has examined if graphene nanoparticles are potentially dangerous for the organism and how cells cope with them once they have been incorporated.

microscopy images of living cells cultured for 36 h without GQDs (left) and with GQDs (right) as observed (top row) and merged with the bright field images (bottom row)

Nanoparticles can be absorbed in body cells, and two aspects to this feature exist. First, it makes nanoparticles good vehicles for transporting a broad range of compounds or substances attached to them into normal diseased cells in a targeted manner. On the other hand, they can also pose health risks.

Dotz Nano has shared a new research that finds its graphene quantum dots (GQDs) technology effective in treating brain injuries, strokes, multiple sclerosis and heart attacks. According to the company, the study demonstrated that these dots, manufactured from coal, can assist in fighting oxidative stress to assist in treating patients suffering from the serious conditions.

Led by the Company's scientific advisor, Professor James Tour, the study was conducted by five universities and research facilities including Rice University, with the findings covered by multiple medical publications.

Researchers from Rice University, the Texas A&M Health Science Center and the McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth) have found that graphene quantum dots drawn from common coal may be the basis for an effective antioxidant for people who suffer traumatic brain injuries, strokes or heart attacks.

Coal-derived graphene quantum dots as seen under an electron microscope

The QDs' ability to quench oxidative stress after such injuries was the subject of a study, which showed that the biocompatible dots, when modified with a common polymer, are effective mimics of the body’s own superoxide dismutase, one of many natural enzymes that keep oxidative stress in check.

Researchers from the Graphene Flagship have developed hybrids of graphene and molybdenum disulphide quantum dots to stabilize perovskite solar cells (PSCs). PSCs are a novel type of solar cells which are efficient, relatively easy to produce, made with cheaper materials and, due to their flexibility, can be used in locations where traditional silicon solar cells cannot be placed.

A collaboration between the Graphene Flagship Partners Istituto Italiano di Technologia, University of Rome Tor Vergata, and BeDimensional resulted in a novel approach based on graphene and related materials to stabilize PSCs, thus addressing the stability issue of PSCs, a major hurdle hindering their commercialization.

Scientists from Manchester University, the Ulsan National Institute of Science & Technology and the Korea Institute of Science and Technology have developed a novel technology, which combines the fabrication procedures of planar and vertical heterostructures in order to assemble graphene-based single-electron transistors.

The schematic structure of the devices

In the study, it was demonstrated that high-quality graphene quantum dots (GQDs), regardless of whether they were ordered or randomly distributed, could be successfully synthesized in a matrix of monolayer hexagonal boron nitride (hBN). Here, the growth of GQDs within the layer of hBN was shown to be catalytically supported by the platinum (Pt) nanoparticles distributed in-between the hBN and supporting oxidised silicon (SiO₂) wafer, when the whole structure was treated by the heat in the methane gas (CH₄). It was also shown, that due to the same lattice structure (hexagonal) and small lattice mismatch (~1.5%) of graphene and hBN, graphene islands grow in the hBN with passivated edge states, thereby giving rise to the formation of defect-less quantum dots embedded in the hBN monolayer.

A new study led by the Ulsan National Institute of Science and Technology in South Korea reveals a technology capable of fabricating highly ordered arrays of graphene quantum dots.

Graphene quantum dots of various sizes in a stable, ordered array

The research team demonstrated a novel way of synthesizing GQDs, embedded inside a hexagonal boron nitride (hBN) matrix. Thus, they demonstrated simultaneous use of in-plane and van der Waals heterostructures to build vertical single-electron tunneling transistors.

Dotz Nano (DTZ) has received a US$100,000 commercial sale of its ValiDotz security-markers and InSpec detectors from a Swiss anti-counterfeiting company offering integrated packaging solutions aimed at governing organizations.

The sale reportedly follows extensive migration testing of Dotz’s anti-counterfeiting markers by the customer, which demonstrated ValiDotz’s accuracy and stability.

The Graphene-Info team takes pleasure in recommending our new book - The Perovskite Handbook. While not focused on graphene, we believe that any person interested in advanced materials and emerging technologies would find that perovskite materials are an area of focus that should not be ignored.

This book gives a comprehensive introduction to perovskite materials, applications and industry. Perovskites offer a myriad of exciting properties and are considered the future of solar cells, displays, sensors, lasers and more. The promising perovskite industry is currently at a tipping point and on the verge of mass adoption and commercialization.

The graphene industry should especially pay attention to perovskites as much work is done on combining these two material technologies to create better solar cells, displays and more.

Scientists from the Center for Nano Energy Materials (CNEM) of Northwestern Polytechnical University in China said they have successfully applied graphene‐enhanced nano-materials to protect ancient wall paintings.

The team used a compound of calcium hydroxide and graphene quantum dots in a water solution and applied the material in ancient wall paintings in three tombs of the Tang Dynasty (618-907). "Research shows that the new material is small (an average of 80 nanometers per particle), uniform in size, and very sticky, thus making it good at reinforcing the wall paintings," Wei Bingqing, a CNEM dean, stated.