Freigeist Fellowship for Tristan Petit
Dr. Tristan Petit will broaden his research on nanocarbon materials with the Freigeist Fellowship. © HZB
For his project on nanodiamond materials and nanocarbon, Dr. Tristan Petit has been awarded a Freigeist Fellowship from the VolkswagenStiftung. The grant covers a five-year period and will enable him to establish his own research team. The VolkswagenStiftung is funding with these prestigious fellowships outstanding postdocs planning original research that transcends the bounds of their own field.
Following his doctoral studies, Dr. Tristan Petit joined the HZB team of Prof. Emad Aziz supported by a post-doctoral stipend from the Alexander von Humboldt Foundation. He had already investigated surface modification of nanodiamonds while exploring their potential for biomedical applications during his doctoral research at the Diamond Sensors Laboratory (CEA) in Gif sur Yvette, France. Petit has since expanded his research interests. This is because nanodiamond materials can also exhibit catalytic effects, in particular when irradiated by sunlight. One dream is to develop synthetic nanodiamond materials for manufacturing solar fuels like methane using sunlight and carbon dioxide, thereby storing solar energy chemically. Aziz and Petit are now working on this project under the European DIACAT research programme.
As a Freigeist Fellow, Petit will investigate how nanocarbon materials in aqueous solutions interact with their environment. These interactions have hardly been studied so far, but they are essential for developing new applications and being better able to assess risks.
It is very difficult to study nanocarbon materials in aqueous solutions experimentally, though. Spectrographic methods using X-ray light can provide information about the electrochemical and photochemical processes. Petit relies on specialised setups for this such as LiXEdrom at BESSY II that were developed at HZB specifically for these kinds of experiments. He intends to use infrared spectroscopy to determine the configuration of water molecules surrounding the nanoparticles. Petit also plans to carry out sequential laser-based pump-probe measurements in order to observe ultrafast electronic processes in the nanoparticles. The methods have already proven themselves in nanocarbon solid-state experiments, but their utilisation in studying nanocarbon in liquids is new, however.
“The Freigeist Fellowship makes it possible for me to research these problems comprehensively. Once we better understand the complex interactions between nanocarbon particles in an aqueous environment, we will be able to develop a new generation of carbon-based nanomaterials for different applications – from photocatalysis of solar fuels to medical applications”, says Petit. The Freigeist Fellowship is accompanied by funding of 805,000 EUR, of which 375,000 EUR is provided by HZB in-house resources and 430,000 EUR by the VolkswagenStiftung.
As a result, there are now two Freigeist Fellows on Aziz’ team. Dr. Annika Bande also received a Freigeist Fellowship last year and has since been working at the HZB Institute for Methods of Material Development headed by Aziz.
Further information on the Freigeist Fellowships: www.volkswagenstiftung.de/freigeist-fellowships.
- 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.