Skip to content

Meet the partners: Reusing recycled materials with RHP Technology

The PHOTORAMA consortium is made up of a team of several organisations, all bringing their specific expertise to the project. We have asked Erich Neubauer from RHP Technology GmbH to tell us more about what the RHP team has been working on so far in PHOTORAMA.

Hello Erich, thanks a lot for taking the time to chat with us today. Can you shortly introduce your organization, and your team and explain its role in PHOTORAMA?

I am Erich Neubauer, I am one of the managing directors and founders of RHP. The company started in 2010 as a spinoff of the Austrian Institute of Technology (AIT). I work together with Zuzana Kovacova on PHOTORAMA, she is mainly responsible for the project at RHP. She is supported by Mariangela Fedel, who is a new team member coming from the nanosynthesis group.

One of our key activities at RHP is the manufacturing of customized sputtering targets which are used as a raw material for thin film coatings in many applications, including in Photovoltaics (PVs).

RHP is a technology development company focusing on advanced materials and processing techniques. This involves sintering, hot-pressing and additives manufacturing. With the help of these technologies, we manufacture customized materials for a large range of customers: we have customers in the PV thin films industry, we manufacture products used for space applications such as in satellites, and we are also making materials for neutron absorption for large entities such as CERN and ESS. Over the past years we have integrated additional manufacturing techniques such as laser-based techniques for the synthesis of nanoparticles.

Our role in PHOTORAMA is to find solutions for the reuse of recycled materials, namely silver, indium, silicon and gallium. With regards to silver, we are using silver precursors (as a starting material), which are coming from PHOTORAMA End-of-Life PV module recycling technologies ‘partner LuxChemtech and using it to coat copper particles. This is an important application because silver inks, which are used in PVs are precious and valuable materials. This is because silver has high electrical conductivity and environmental stability. Copper, which is cheaper, is not as attractive, because despite its high electrical conductivity it can oxidate. Our idea is to use copper particles coated by silver coming from recycled PV. This means that we protect the copper from oxidation and that gives two benefits: we can use the precursor materials from the recycling and we can reduce the amount of silver that is needed because we replace the core by copper, which is cheaper. We also use recycled silver by integrating silver particles into pastes and inks, which can be reused in PV but also in other electronics, printed electronics for example (3D printing). This is possible thanks to our nanopowder synthesis technology, where we use raw materials from LuxChemtech to create nano-particles with a laser-based process.

We also work with recycled indium.  In PV cells there is typically a material called indium tin oxide (ITO) which is used as a transparent conductive. After the recycling process we either obtain indium metal or indium oxide or hydroxide. Indium metal can be used for the bounding of sputtering targets. The advantage of metallic indium is that it has a low melting point and thus can be used for the bonding of the sputtering targets needed in PV but also in other applications.  In the case of indium oxide or hydroxide, we can combine it with virgin materials to create oxide thin films which require very high purity levels.

The third material that we work with, silicon, is introduced into aluminium alloys. They do not require a high material purity level and as such recycled silicon can more easily be introduced in such a product.  The output is silicon-rich alloys, which have specific thermal characteristics. It has good conductivity and its coefficient of expansion is low, which means that it does not expand much when heated. This material is especially interesting for applications destined to cool electronics. In addition, we are able to create 3D metallic structures by inserting the alloys into a plasma arc and by melting it.

The last material that we are dealing with is gallium.  The quantities of gallium that will be generated by the project will be limited, as it is used in very specific thin films. One of the reuse applications would be to use gallium again for sputtering targets.

What are you currently working on? What is happening now?

Currently, our focus is on silver and silicon. We have already demonstrated the coating of copper particles by a silver coating process. They have been introduced in paste manufacturing and from there we are evaluating their performance. With regards to silicon, we are facing the challenge of handling a large range of particle sizes coming out of the recycling. We are working on identifying and extracting the correct size for subsequent processing.

What does your specific expertise add to the consortium?

RHP is an expert in a large variety of materials from metals, ceramics, alloys to composite materials. Over the past 10 years, we have done more than 1000 different compositions—and gained considerable knowledge of the materials that we are working with.  The customization of materials used for thin films according to customer requirements is also one of our main strengths: where we can work flexibly with different types of materials for different uses. This is key when working with recycled products.

In addition, our company is not only involved in developing technologies but our goal is to transfer our technologies into commercial products.

Why, according to you, do we need a project like PHOTORAMA?

Recycling is becoming more and more relevant. When looking at sputtering targets, which are often included in consumer goods, 60-70% are lost after use. That is problematic. Reusing such high-value products is important to avoid unnecessary waste. In addition, from our company’s perspective, recycling concepts creates a better connection with our customers.  If a customer is buying a high price product, they have an interest to reuse part of the product and get something back by using recycled products. In addition, this is just better for the environment.

What is the biggest challenge to bring upon PV circularity?

The challenge in our case concerns mostly the available quantities of indium and gallium. Right now, there is not enough volume to treat it efficiently.  

What would you like to have achieved at your scale by the end of the project?

We would like to prove that paste and inks based on recycled materials can be used directly in other products such as PVs.

Thank you Erich for this overview of RHP’s work in PHOTORAMA!