Traceable characterisation of thin-film materials for energy applications

The European Union is aiming to generate at least 32 % of all power from renewable sources by 2030, which will require the development of new technologies. Ultra-thin films are a component in many energy-critical applications such as solar panels, energy-efficient windows and power electronics that control the flow of electricity from the grid. Formed of multiple layers of different materials, such films have novel electronic and thermal properties for which correctly-manufactured composition is integral to functionality and reliability. However, a lack of agreement about which measurement parameters are most important for optimising performance, along with quality issues during development, hamper product development and the market competitiveness of thin-films.

This project developed a multi-faceted metrology framework for reliable analysis of these materials and demonstrated improved efficiency and stability in these products.

The project:

• Developed a new coating method that increased the life-span of thin films or improved efficiency.
• Developed new optical and X-ray analysis methods for characterising thin film surfaces, devices and underlying chemistries to unprecedented levels of accuracy.
• Published four good practice guides that describe analytical techniques to best characterise thin-film energy materials.

Delivering impact
The developed protective coating technique enabled the creation of solar cells with increased efficiency that led to the formation of ELFys Inc., manufacturers of high-efficiency photodetectors. The X-ray analysis methods developed in this project, capable of determining the composition, density and thermal diffusivity of thin films over a wide range of temperatures and photon energies have led to the creation of a new measurement facility, important in both power electronics and solar cell applications. These methods are being further developed to enable their use in online process-control during thin film deposition.

Following the project, the measurement institutes PTB, VSL and NPL now offer consultancy services to EU companies in the X-ray, optical and optoelectronic measurement fields, to help improve product performance. Along with the best practice guides, a new German DIN standard was developed scheduled for publication as an international ISO standard.

Cumulatively, these new metrological tools will advance European competitiveness and innovation capability in energy efficiency technologies and, therefore, help meet renewable energy targets. The follow on project  Hybrid metrology for thin films in energy applications continued research in this field.