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A new phosphor for more efficient lighting Researchers from KU Leuven have discovered a new phosphor that could make next-generation fluorescent and LED lighting even cheaper and more efficient. Writing in the journal Nature Materials, the team described their

In collaboration with Professor Peter Lievens’ Laboratory of Solid-State Physics and Magnetism, the researchers examined the properties of these heat-treated ‘silver zeolites’ and found that the structural, electronic and optical properties of the

use of highly luminescent clusters of

zeolites were strongly influenced by the

silver atoms and the porous framework

silver clusters. That’s how they discovered

of minerals known as zeolites.

that the shape of the silver clusters is

Silver clusters consist of just a few silver atoms and have remarkable optical properties. However, current applications are limited as the clusters tend to aggregate into larger particles, thus losing the interesting optical properties. Professor Johan Hofkens and his team from KU Leuven’s Molecular Imaging and Photonics unit have

essential to obtain the right fluorescence properties. “Clusters of silver atoms can assemble into different shapes, including a line or a pyramid,” said Professor Hofkens. “This pyramid shape is what we need to obtain the best fluorescence properties. Heating up the silver ions in the zeolite framework makes them adopt this shape.

now found a way to keep the silver clusters apart by inserting

Because they are ‘trapped’, as it were, in the cages of the zeolites,

them into the porous framework of zeolites.“Zeolites contain

they can only form a pyramid with up to four silver atoms. That

sodium or potassium ions,” explained Professor Maarten

is exactly the shape and size in which the silver cluster emits the

Roeffaers from the Centre for Surface Chemistry and Catalysis.

largest amount of fluorescent light, with an efficiency close to 100%.”

“We used ion exchange to replace these ions with silver ions.

The new phosphors not only emit a large amount of light,

To obtain the clusters we wanted, we heated up the zeolites

they are also cheap to produce. The findings therefore have great

with the silver ions so that the silver ions self-assembled

potential for the development of next-generation fluorescent and

into clusters.”

LED lighting and for biological imaging.

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Sustainability Matters Aug/Sep 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...

Sustainability Matters Aug/Sep 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...