Interview with MIT-Expert Harry Tuller
Prof. Dr. Harry Tuller, MIT, was a guest-scientist at the institute for solar fuels.
When can we hope to store solar energy in form of hydrogen with an efficient and cheap solution? What is motivating young people to get involved into science these days? And how does is come that many scientists really love to work, even after the official retirement age? Prof. Dr. Harry Tuller ist answering these questions in an interview, which you can listen here. And if you prefer to read his answers, you could download the transcript.
In summer 2013, Professor Harry Tuller was visiting the HZB for several weeks. His visit was sponsored by a Helmholtz International Fellowship Award. Tuller is an expert in the field of fuel cells, batteries and new solutions for energy transformation at the world famous Massachusetts Institute of Technology, USA.
The Interview:
- CIGS-perovskite tandem cell achieves record efficiency of 25.5 %A Berlin-based team from HZB and Center for the Science of Materials Berlin (CSMB) at the Humboldt-Universität zu Berlin has set a new record for a tandem solar cell. Using a combination of a CIGS semiconductor layer and perovskite, along with several optimised intermediate layers, they were able to convert 25.5% of sunlight into electrical energy. The previous record for this combination of materials and this size of cell stood at 24.6%. The new record has been certified and is visible in the prestigious Solar Cell Efficiency Tables (the "Green Tables"), which serve as the definitive ledger for the global photovoltaic community.
- Disorder creates new properties in compound semiconductorsAn international research team has demonstrated that the intrinsic disorder of the compound semiconductor CuInSnS₄ can be exploited to influence its optical properties. While the atomic vibrations also sense the local disorder, their response is averaged over many different local environments and therefore appear isotropic, as expected for a cubic crystal. In contrast, the optical excitations, known as excitons, are much more sensitive to the local arrangement of atoms. Surprisingly, they show a direction-dependent optical response even though the average crystal structure is cubic. These findings shed new light on the relationship between disorder and material properties, opening up new options for targeted 'disorder engineering' in optoelectronic and photocatalytic devices.
- Perovskite solar cells: Predictions of long-term stabilityReliable statements about the long-term stability of perovskite solar cells are still difficult to make. However, a new study by Dr Carolin Ulbrich’s team, published in the renowned journal Joule, highlights which methods are useful for this purpose and identifies areas where further research is needed.