UK researchers demonstrate a viable graphene-based OLED encapsulation solution

OLED displays are very sensitive to oxygen and moisture, and the need to protect the displays is one of the major challenges of this next-generation display technology. First generation OLED displays were protected with a glass barrier, but glass is not easily flexible and so cannot be used in flexible OLEDs. Flexible OLEDs are today encapsulation with a thin-film encapsulation layer made from both organic and in-organic materials, and companies are searching for better OLED encapsulation technologies.

Graphene encapsulation research, CPI 2017

Graphene is the world's most impermeable material, and so the idea of using graphene as a barrier layer for OLED has been around for a while. In 2015 the UK launched a collaboration project called Gravia to develop graphene-based encapsulation, and the project's team has now reported their results.

Chinese scientists design a flexible graphene-based energy storage membrane

Researchers from Tsinghua University in China have designed a low-cost energy storage device using a TiO2-assisted UV reduction of sandwiched graphene components. The sandwich structure consists of two active layers of reduced graphene oxide hybridized with TiO2, with a graphene oxide separator (rGO-TiO2/rGO/rGO-TiO2). In the device, the separator layer also acts as a reservoir for the electrolyte, which affects ion diffusion—a known problem for layered membrane devices—and affects both the capacity and rate performance.

Graphene flexible supercapacitor membrane process image

The team explained that a step-by-step vacuum filtration process is used to form the membrane structure, and the amount of graphene oxide used in the filtration solutions can be adjusted to precisely tune the thickness of each layer. Irradiation of the dried membrane with UV light then reduces the graphene oxide to rGO with assistance from the TiO2.

Researchers design a spray-on sensing technology that detects structural integrity

A team of researchers from Hong Kong Polytechnic University (PolyU) has developed sensors which can be sprayed directly onto flat or curved surfaces. The sensors, made from a hybrid of carbon black (CB), graphene, other conductive nano-scale particles, and polyvinylidene fluoride (PVDF), can be networked to extract rich real-time information on the health status of the structure being monitored.

The technology includes a sensor network with a number of the sprayed nanocomposite sensors and an ultrasound actuator to actively detect the health condition of the structure to which they are fixed. When the ultrasound actuator emits guided ultrasonic waves (GUWs), the sensors will receive and measure the waves. If damage is detected, such as a crack in the structure, propagation of GUWs will be interfered by the damage, leading to the wave scattering phenomena to be captured by the sensor network. The damage can then be characterised quantitatively and accurately.

Chinese team created graphene aerogels inspired by plant structure

Researchers at Zhejiang University in China have designed a graphene-based aerogel mimicking the structure of the "powdery alligator-flag" plant that could have potential for use in applications like flexible electronics.

Graphene aerogel based on plant structure image

The team drew inspiration from the stem structure of the powdery alligator-flag plant (Thalia dealbata), a strong, lean plant capable of withstanding harsh winds. The researchers used a bidirectional freezing technique that they previously developed to assemble a new type of biomimetic graphene aerogel that had an architecture like that of the plant's stem. When tested, the material supported 6,000 times its own weight and maintained its strength after intensive compression trials and was resilient. They also put the aerogel in a circuit with a LED and found it could potentially work as a component of a flexible device.

Graphene-based contact lens sensor for diabetes monitoring

Researchers affiliated with UNIST have raised the possibility of in-situ human health monitoring by wearing a contact lens with built-in wireless smart sensors. Towards this end, the team made use of smart contact lens sensors with electrodes made of graphene sheets and metal nanowires.

Graphene lens sensor for disease monitoring image

The smart contact lens sensor could help monitor biomarkers for intraocular pressure (IOP), diabetes mellitus, and other health conditions. The research team expects that this research breakthrough could lead to the development of biosensors capable of detecting and treating various human diseases, and used as a component of next-generation smart contact lens-related electronic devices.