. 24/7 Space News .
Decoding the structure and properties of near-infrared reflective pigments
by Staff Writers
Nagoya, Japan (SPX) Jul 26, 2022

In a new study, researchers from Nagoya Institute of Technology, Japan use a combination of experimental and theoretical approaches to understand the optical, electronic, and magnetic properties of complex solids of layered perovskite compounds, providing valuable insights. The approach is extendable to a wide range of functionalized crystalline ceramic compounds.

Urban areas without sufficient tree cover are significantly warmer than their surroundings. This "urban heat island" effect mainly results from an absorption of near-infrared (NIR) radiation in sunlight. NIR-reflective pigments that can mitigate such heating effects are, therefore, highly desirable.

In particular, functional inorganic pigments are an attractive candidate on this front. In fact, Dr. Ryohei Oka and his colleague from Nagoya Institute of Technology, Japan, have demonstrated that layered perovskite ceramic compounds of the type A2BO4 are ideal for reflecting NIR.

In his previous study, it was discovered that novel perovskites such as titanium-added calcium manganese oxide (Ca2(Mn,Ti)O4) ceramics are much better at reflecting NIR radiation than commercially available black pigments. However, the mechanism by which Ca2(Mn,Ti)O4 achieves this remarkable feat remains unknown.

In a recent study published in Inorganic Chemistry, Dr. Oka and his colleague, Dr. Tomokatsu Hayakawa, analyzed the structure and composition of Ca2(Mn,Ti)O4 using a combination of standard theoretical and experimental techniques to investigate the factors contributing to its enhanced NIR reflectivity. This paper was made available online on April 19, 2022, and published in Volume 61 Issue 17 of the journal on May 2, 2022.

In their work, the duo employed X-Ray diffraction (XRD) and Raman spectroscopy in combination with a computational method called "density functional theory" (DFT) to successfully extract missing details about the crystal structure and electronic states of Ca2(Mn,Ti)O4.

"Few studies so far have conducted Raman spectroscopy of Ca2(Mn,Ti)O4. Furthermore, they have not provided any detail of its vibrational modes. However, information about its electronic states and vibrational modes is crucial to understand how these perovskites turn out to be such great NIR reflectors," says Dr. Oka, explaining the motivation behind their approach.

The duo analyzed the crystal structure of calcium manganese oxide (Ca2MnO4) and tracked the structural changes that occurred with the addition of Ti impurities. Furthermore, they identified how the chemical bonds within the perovskite are modified upon introducing Ti impurities.

They found that, compared to Ca2MnO4, Ca2(Mn,Ti)O4 exhibited an additional Raman peak that was likely due to the activation of a "silent mode" caused by the Ti impurities. However, the XRD patterns of Ca2MnO4 and Ca2(Mn,Ti)O4 were identical. The duo attributed this to Ti-Ti correlation at a certain distance.

Another highlight of their study was the striking agreement between computational results from DFT and experimental data. The energy gaps obtained from the three models for Ca2(Mn,Ti)O4 used by the duo in their calculations agreed with each other as well as the experimental value. Moreover, the result was independent of Ti-substitution or its position in the crystal.

Additionally, the calculations revealed that the enhanced NIR reflectivity upon adding Ti ions resulted from a lowering of "density of states" (the number of electronic states per unit volume per unit energy) near the Fermi level (the highest energy level an electron can occupy at absolute zero temperature).

These findings take us a step closer towards unveiling the thermal shielding property of perovskite ceramics. The perfect combination of experimental and theoretical approaches developed in this study provides a general recipe for understanding the structure and properties of not only A2BO4 type ceramics but a range of complex perovskite ceramics.

As Dr. Oka puts it, "This combinational approach is applicable to a wide range of functionalized crystalline ceramics to understand their optical, electronic, and magnetic properties in a much better way with more reliable structural models obtained computationally."

Indeed, the detailed understanding of the enhanced NIR reflection mechanism would be extremely beneficial as inorganic pigments find more application as superior thermal coatings for urban buildings.

Research Report:Raman Spectroscopic Investigation and Electronic State Calculation for Ca2(Mn,Ti)O4 Black Pigments with High Near-Infrared (NIR) Reflectivity

Related Links
Nagoya Institute of Technology
Space Technology News - Applications and Research

Thanks for being there;
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 Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Floors in ancient Greek luxury villa were laid with recycled glass
Odense, Denmark (SPX) Jul 26, 2022
Although this 1700 years old luxury villa was excavated and examined both in 1856 and in the 1990s, it still has secrets to reveal. New secrets have now been revealed by an international research team, with Professor and expert in archaeometry, Kaare Lund Rasmussen from University of Southern Denmark leading the so called archaeometric analyses: using chemical analysis to determine which elements an object was made of, how it has been processed, etc. Others in the team are Thomas Delbey from ... read more

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

Space For Humanity will send first Egyptian to space via Blue Origin

Russian, European astronauts make rare joint spacewalk at ISS

Dragon docks at ISS to deliver various science payloads

US renews space flights with Russia in rare cooperation

CAA launches consultation on UK space launch from Cornwall

Marine Management Organisation opens consultation on Virgin Orbit launch site

Northrop Grumman and NASA test SLS booster

Rocket launches can create night-shining clouds away from the poles

Laser marking on Mars

Mars dust as a basis for life? no problem for certain bacteria

Unequal siblings: Ius and Tithonium Chasma

When Mars throws you a curveball Sol 3539-3540

New Chinese rocket makes debut flight

China's space station expanding nation technology base

Chinese astronauts set up new lab on space station

China's newest research lab prepares launch to space

Terran Orbital Commissions Fleet Space CENTAURI-5 Payload

Eutelsat and OneWeb to Combine: Company Statement

SpaceX launches another 53 Starlink satellites in sixth launch of month

Satellite operators Eutelsat and OneWeb eye possible merger

Raytheon to upgrade Australian border surveillance aircraft with advanced radar

Decoding the structure and properties of near-infrared reflective pigments

Innovation with the additive advantage

Understanding friction, the unavoidable enemy

How do collisions of rocks with planets help the planets evolve?

Lava caves of Hawaii Island contain thousands of unknown bacterial species

A New Method to Detect Exoplanets

Rocking shadows in protoplanetary discs

Why Jupiter doesn't have rings like Saturn

You can help scientists study the atmosphere on Jupiter

SwRI scientists identify a possible source for Charon's red cap

NASA's Europa Clipper Mission Completes Main Body of the Spacecraft

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - 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. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.