Category Physics

How does visible light communications (VLC) work? Credit: pureLiFi

Will solar-powered wireless communication benefit millions in the years to come? That is the hope of enthusiasts seeing a future in Li-Fi, wireless technology which is wireless—only not as we know it. Li-Fi, coined by University of Edinburgh’s Professor Harald Haas, is a wireless technology which refers to visible light communications (VLC) technology delivering a high-speed, bidirectional networked, mobile communications in a similar manner as Wi-Fi.

How does visible light communications (VLC) work? Credit: pureLiFi

Li-Fi technology can be integrated with solar cells to receive data. Solar panels on houses or smart watches can absorb power and receive data at the same time...

Quick and easy coating process makes surfaces omniphobic. (© Wiley) Read more: Totally repellent – Quick and easy coating process makes surfaces omniphobic

Surfaces that repel all dirt and graffiti, are easy to clean, and cause liquids to bead up and slide off (like the frequently mentioned lotus blossom), are high on the wish lists of engineers and scientists. However, none of the technologies developed in the past has been a sweeping success. Scientists have now introduced a new method for making transparent, dirt-repellant coatings that can be applied very quickly and easily. The coatings repel both water and oily liquids and are stable at higher pressures and temperatures.

Prior approaches involved fluoropolymers (e.g. Teflon) and silicones...

Nearly 32X more sensitive than microphones of standard nickel-based construction, University of Belgrade researchers created a vibrating membrane – the part of a condenser microphone which converts the sound to a current, from graphene, with up to 15 dB higher sensitivity compared to a commercial microphone, at frequencies up to 11 kHz.

“We wanted to show that graphene, although a relatively new material, has potential for real world applications” explains Marko Spasenovic. “Given its light weight, high mechanical strength and flexibility, graphene just begs to be used as an acoustic membrane material.”

The graphene membrane, approximately 60 layers thick, was grown on a nickel foil using chemical vapour deposition, to ensure consistent quality across all the samples...

Schematic of a laser beam energizing a monolayer semiconductor made up of molybdenum disulfide (MoS2). The red glowing dots are particles excited by the laser. Credit: Der-Hsien Lien Read more at: http://phys.org/news/2015-11-defect-free-molecule-thick.html#jCp

An emerging class of atomically thin materials, monolayer semiconductors has generated a great deal of buzz in the world of materials science. Monolayers hold promise in the development of transparent LED displays, ultra-high efficiency solar cells, photo detectors and nanoscale transistors. Their downside? The films are notoriously riddled with defects, killing their performance.

But a UCLA, Berkeley, and Lawrence Berkeley National Lab team, has found a simple way to fix these defects via an organic superacid...