Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



TECH SPACE
Making glass invisible
by Staff Writers
Upton NY (SPX) Nov 01, 2017


Glass surfaces with etched nanotextures reflect so little light that they become essentially invisible. This effect is seen in the above image, which compares the glare from a conventional piece of glass (right) to that from nanotextured glass (left), which shows no glare at all.

If you have ever watched television in anything but total darkness, used a computer while sitting underneath overhead lighting or near a window, or taken a photo outside on a sunny day with your smartphone, you have experienced a major nuisance of modern display screens: glare. Most of today's electronics devices are equipped with glass or plastic covers for protection against dust, moisture, and other environmental contaminants, but light reflection from these surfaces can make information displayed on the screens difficult to see.

Now, scientists at the Center for Functional Nanomaterials (CFN) - a U.S. Department of Energy Office of Science User Facility at Brookhaven National Laboratory - have demonstrated a method for reducing the surface reflections from glass surfaces to nearly zero by etching tiny nanoscale features into them.

Whenever light encounters an abrupt change in refractive index (how much a ray of light bends as it crosses from one material to another, such as between air and glass), a portion of the light is reflected. The nanoscale features have the effect of making the refractive index change gradually from that of air to that of glass, thereby avoiding reflections.

The ultra-transparent nanotextured glass is antireflective over a broad wavelength range (the entire visible and near-infrared spectrum) and across a wide range of viewing angles. Reflections are reduced so much that the glass essentially becomes invisible.

This "invisible glass" could do more than improve the user experience for consumer electronic displays. It could enhance the energy-conversion efficiency of solar cells by minimizing the amount of sunlight lost to refection.

It could also be a promising alternative to the damage-prone antireflective coatings conventionally used in lasers that emit powerful pulses of light, such as those applied to the manufacture of medical devices and aerospace components.

"We're excited about the possibilities," said CFN Director Charles Black, corresponding author on the paper published online on October 30 in Applied Physics Letters. "Not only is the performance of these nanostructured materials extremely high, but we're also implementing ideas from nanoscience in a manner that we believe is conducive to large-scale manufacturing."

Former Brookhaven Lab postdocs Andreas Liapis, now a research fellow at Massachusetts General Hospital's Wellman Center for Photomedicine, and Atikur Rahman, an assistant professor in the Department of Physics at the Indian Institute of Science Education and Research, Pune, are co-authors.

To texture the glass surfaces at the nanoscale, the scientists used an approach called self-assembly, which is the ability of certain materials to spontaneously form ordered arrangements on their own.

In this case, the self-assembly of a block copolymer material provided a template for etching the glass surface into a "forest" of nanoscale cone-shaped structures with sharp tips - a geometry that almost completely eliminates the surface reflections. Block copolymers are industrial polymers (repeating chains of molecules) that are found in many products, including shoe soles, adhesive tapes, and automotive interiors.

Black and CFN colleagues have previously used a similar nanotexturing technique to impart silicon, glass, and some plastic materials with water-repellent and self-cleaning properties and anti-fogging abilities, and also to make silicon solar cells antireflective.

The surface nanotextures mimic those found in nature, such as the tiny light-trapping posts that make moth eyes dark to help the insects avoid detection by predators and the waxy cones that keep cicada wings clean.

"This simple technique can be used to nanotexture almost any material with precise control over the size and shape of the nanostructures," said Rahman. "The best thing is that you don't need a separate coating layer to reduce glare, and the nanotextured surfaces outperform any coating material available today."

"We have eliminated reflections from glass windows not by coating the glass with layers of different materials but by changing the geometry of the surface at the nanoscale," added Liapis. "Because our final structure is composed entirely of glass, it is more durable than conventional antireflective coatings."

To quantify the performance of the nanotextured glass surfaces, the scientists measured the amount of light transmitted through and reflected from the surfaces. In good agreement with their own model simulations, the experimental measurements of surfaces with nanotextures of different heights show that taller cones reflect less light.

For example, glass surfaces covered with 300-nanometer-tall nanotextures reflect less than 0.2 percent of incoming red-colored light (633-nanometer wavelength). Even at the near-infrared wavelength of 2500 nanometers and viewing angles as high as 70 degrees, the amount of light passing through the nanostructured surfaces remains high - above 95 and 90 percent, respectively.

In another experiment, they compared the performance of a commercial silicon solar cell without a cover, with a conventional glass cover, and with a nanotextured glass cover. The solar cell with the nanotextured glass cover generated the same amount of electric current as the one without a cover.

They also exposed their nanotextured glass to short laser pulses to determine the intensity at which the laser light begins to damage the material. Their measurements reveal the glass can withstand three times more optical energy per unit area than commercially available antireflection coatings that operate over a broad wavelength range.

"Our role in the CFN is to demonstrate how nanoscience can facilitate the design of new materials with improved properties," said Black. "This work is a great example of that - we'd love to find a partner to help advance these remarkable materials toward technology."

Research paper

TECH SPACE
MIT students fortify concrete by adding recycled plastic
Boston MA (SPX) Oct 26, 2017
Discarded plastic bottles could one day be used to build stronger, more flexible concrete structures, from sidewalks and street barriers, to buildings and bridges, according to a new study. MIT undergraduate students have found that, by exposing plastic flakes to small, harmless doses of gamma radiation, then pulverizing the flakes into a fine powder, they can mix the plastic with cement p ... read more

Related Links
Brookhaven National Laboratory
Space Technology News - Applications and Research


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TECH SPACE
Plants and psychological well-being in space

Spacewalkers fix robotic arm in time to grab next cargo ship

NASA develops and tests new housing for in-orbit science payloads

Russia's space agency says glitch in manned Soyuz landing

TECH SPACE
Thruster for Mars mission breaks records

Draper and Sierra Nevada Corporation announce new agreement for space missions

Aerojet Rocketdyne breaks ground on advanced manufacturing center in Huntsville

New solid rocket motor development facility completed at Spaceport America

TECH SPACE
Mars Rover Mission Progresses Toward Resumed Drilling

Solar eruptions could electrify Martian moons

MAVEN finds Mars has a twisted tail

Mine craft for Mars

TECH SPACE
Space will see Communist loyalty: Chinese astronaut

China launches three satellites

Mars probe to carry 13 types of payload on 2020 mission

UN official commends China's role in space cooperation

TECH SPACE
Myanmar to launch own satellite system-2 in 2019: vice president

Eutelsat's Airbus-built full electric EUTELSAT 172B satellite reaches geostationary orbit

Turkey, Russia to Enhance Cooperation in the Field of Space Technologies

SpaceX launches 10 satellites for Iridium mobile network

TECH SPACE
Turning a material upside down can sometimes make it softer

Nanoscale textures make glass invisible

New property found in unusual crystalline materials

MIT students fortify concrete by adding recycled plastic

TECH SPACE
Comet mission reveals 'missing link' in our understanding of planet formation

New NASA study improves search for habitable worlds

From Comets Come Planets

A star that devoured its own planets

TECH SPACE
Haumea, the most peculiar of Pluto companions, has a ring around it

Ring around a dwarf planet detected

Helicopter test for Jupiter icy moons radar

Solving the Mystery of Pluto's Giant Blades of Ice




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement