Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New concept for structural colors

18.05.2018

Scientists of the University of Hamburg (TUHH), the ITMO-University in St. Petersburg and the Helmholtz-Center Geesthacht have developed a novel concept that enables colorants which are based on non-toxic materials, which further do not bleach in the sunlight and which do not lose their appearance under high processing temperatures (as needed for glazes of ceramics).

In contrast to conventional pigments, the color effect is not caused by the absorption of certain wavelengths, which are in turn missing from the reflection spectrum and thus cause the color impression. Structural colors generate color solely by a structure that lets certain wavelengths destructively interfere.


Abbildung: Vergleich der berechneten Reflexionsspektren zweier photonischer Gläser, einmal bestehend aus keramischen Vollkugeln (a) und einmal aus keramischen Hohlkugeln (b). Die Kugeldurchmesser betragen ca. 200 Nanometer und die Schalendicke der Hohlkugeln in (b) ca. 10 Nanometer.

Das rechte Bild zeigt ein wesentlich steileres Reflexionsspektrum, das eine bessere Farbsättigung der in diesem Fall blauen Farbe bedingt.

Die beiden Quader zeigen Ausschnitte der mit Kugeln befüllten Volumina, mittels derer die numerischen Simulationen durchgeführt wurden.

(b) Chromatizitätsdiagramm. Die Positionen der beiden Reflexionsspektren in (a) und (b) sind in Relation zum farblosen Weißpunkt eingetragen. Auf dem Umfang des Diagramms sind die reinen Farben gezeigt.

Das aus Hohlkugeln bestehende photonische Glas erzeugt eine Farbe, die im Vergleich zu dem aus Vollkugeln bestehenden photonischen Glas wesentlich näher am Umfang liegt – also viel reiner ist.

Often such pigments feature a color impression that is dependent on the direction of illumination as well as the angle under which the pigment is looked at. This one wants to prevent in many cases. To realize “non-iridescent” colors, a certain amount of disorder in the structural arrangement of the colorant is needed. However, this disorder has lead, so far, to only weakly saturated colors.

The group of Hamburg based scientist have managed now to resolve these conflicting requirements. For this purpose a new concept was developed, which is based on weakly ordered arrangements of spheres – a so called photonic glass – combined with a precise design of the spheres themselves.

The utilized hollow spheres have a diameter of around 200 nanometers with a ceramic shell of only around 10 nanometers thickness. Only the combination of the nearest neighbor ordering of these densely packed spheres and the hollow sphere character of the single particles allow a steep edge of the reflection spectrum (Figure 1b). The usefulness of this design approach is exemplified with a highly saturated blue color.

The photonic glass from hollow sphere particles produces a blue color much closer to the perimeter of the chromaticity diagram, thus a much purer color than that of the photonic glass from homogeneously filled spheres (Figure 1c). The team of researchers developed the theoretical framework for the description of this novel class of colorants and confirmed their predictions with extensive numerical simulations.

These principal findings which were produced under the lead of the scientists from Hamburg are further of importance for the development of non-toxic colorants, which also do not bleach under sun light and which are suited for high processing temperatures beyond 1000°C.

The manuscript was published in Scientific Reports, an Open Access-Journal of Nature.

Online: www.nature.com/articles/s41598-018-26119-8

Publication:
Guoliang Shang, Lukas Maiwald, Hagen Renner, Dirk Jalas, Maksym Dosta, Stefan Heinrich, Alexander Petrov, and Manfred Eich,
Photonic glass for high contrast structural color,
Scientific Reports, 8, 7804 (2018)

Further Information
Prof. Dr. Manfred Eich
Technische Universität Hamburg-Harburg (TUHH), Institut für Optische und Elektronische Materialien, Eißendorfer Straße 38, D-21073 Hamburg
und
Institut für Werkstoffforschung, Helmholtz-Zentrum Geesthacht, Max-Planck-Strasse 1, Geesthacht, D-21502, Germany,
Tel +49 40 42878 3147
E-Mail: m.eich@tuhh.de,
Website: www.tuhh.de/alt/oem/home.html

Jasmine Ait-Djoudi | idw - Informationsdienst Wissenschaft
Further information:
http://www.tuhh.de

More articles from Materials Sciences:

nachricht Synthesis of helical ladder polymers
21.05.2019 | Kanazawa University

nachricht Ultra-thin superlattices from gold nanoparticles for nanophotonics
21.05.2019 | Heinrich-Heine University Duesseldorf

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

Im Focus: A step towards probabilistic computing

Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future

When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...

Im Focus: Recording embryonic development

Scientists develop a molecular recording tool that enables in vivo lineage tracing of embryonic cells

The beginning of new life starts with a fascinating process: A single cell gives rise to progenitor cells that eventually differentiate into the three germ...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Summit charts a course to uncover the origins of genetic diseases

22.05.2019 | Life Sciences

New study finds distinct microbes living next to corals

22.05.2019 | Life Sciences

Stellar waltz with dramatic ending

22.05.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>