Sustainability over the entire life cycle

(Nanowerk News) Organic electronics can make a decisive contribution to decarbonization and, at the same time, help reduce consumption of rare and valuable raw materials. To do so, it is necessary not only to further develop the manufacturing process, but also to design technical solutions for recycling from the laboratory stage. Materials scientists from the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) are now promoting this circular strategy together with researchers from the UK and the US in the journal Natural Ingredients (“Sustainability considerations for organic electronic products”).

Organic electronic components, such as solar modules, have several outstanding features. They can be applied in very thin layers on flexible carrier materials and therefore have a wider range of applications than crystalline materials. Because their photoactive substances are carbon-based, they also contribute to reducing consumption of rare, expensive, and sometimes toxic materials such as iridium, platinum, and silver.

Organic electronic components are experiencing major growth in the area of ​​OLED technology in particular, and especially for television or computer displays.

“On the one hand, this is progress, but on the other hand it raises some problems,” said Prof. Dr. Christoph Brabec, Chair of Materials Science (Materials in Electronic and Energy Technology) at FAU and Director of the Helmholtz Erlangen Institute -Nürnberg for Renewable Energy (HI ERN).

As a materials scientist, Brabec sees the dangers of permanently incorporating environmentally friendly technologies into the overall unsustainable device architecture. This affects not only electronic devices, but also organic sensors in textiles which have a very short lifetime.

Brabec: “Applied research in particular must now set a course to ensure that electronic components and all their individual parts must leave as small an ecological footprint as possible over their entire life cycle.”

More efficient synthesis and stronger materials

Further development of organic electronics itself is fundamental here, as new materials and more efficient manufacturing processes lead to reduced expenditure and energy during production.

“Compared to simple polymers, the process of creating photoactive coatings requires a much higher amount of energy because they are stored in a vacuum at high temperatures,” explains Brabec.

Therefore, the researchers proposed cheaper and more environmentally friendly processes, such as precipitation from aqueous solutions and printing using an inkjet process.

Brabec: “One of the main challenges was developing functional materials that could be processed without toxic solvents that are harmful to the environment.” In the case of OLED screens, inkjet printing also offers the possibility of replacing precious metals such as iridium and platinum with organic materials.

In addition to its efficiency, the stability of the material’s operation is very decisive. The complex encapsulation is required to protect the vacuum-stored carbon layer of organic solar modules, which can make up two-thirds of their total weight. Stronger material combinations can contribute to significant material, weight and energy savings.

Plan the recycling process in the laboratory

To make a realistic evaluation of the environmental footprint of organic electronics, the entire product life cycle must be considered. In terms of output, the organic photovoltaic system still lags behind conventional silicon modules, but has 30% less CO22 emitted during the manufacturing process.

Aiming for maximum efficiency levels isn’t everything, says Brabec: “18 percent could be more environmentally reasonable than 20, if it is possible to make photoactive materials in five steps instead of eight.”

In addition, the relatively shorter operating life of the organic modules, if you look closely. Although silicon-based photovoltaic modules last longer, they are very difficult to recycle.

“Biocompatibility and biodegradability will increasingly become important criteria, both for product development and packaging design,” said Christoph Brabec. “We really need to start considering recycling in the lab.”

This means, for example, using a substrate that can be easily recycled or that is as biodegradable as the active ingredient. Using what is known as a multilayer design since the product design phase can ensure that the various materials can be easily separated and recycled at the end of the product’s life cycle.

Brabec: “This cradle-to-cradle approach will be a decisive prerequisite for establishing organic electronics as a critical component in the transition to renewable energy.”