poster prize for Laura Elisa Valle Rios student at the European Crystallographic Meeting (ECM29)
price ceremony at the ECM29
The poster contribution of Laura Elisa Valle Rios (HZB-Department Crystallography) was awarded the CrystEngComm poster price of the Royal Society of Chemistry at the 29th European Crystallographic Meeting (ECM29) in Rovinj (Croatia). Laura Elisa, a PhD student in the Marie-Curie Initial Training network KESTCELLS and the HZB Graduate School "Materials for Solar Energy Conversion" (MatSEC).
She presented results on structural properties of Kesterites (Cu2ZnSnSe4 - CZTSe) in relation to its stoichiometry deviations.
The best performances of Kesterite-based thin film solar cells with converion efficiencies of 12.6% were obtained with an absorber material quite different from the stoichiometric compound Cu2ZnSn(S,Se)4, especially with a Cu-poor/Zn-rich composition. Because the electronic properties of a semiconductor are strongly related to its crystal structure, it is of great interest to study the nature of stoichiometry deviations systematically and to connect issues such as phase existence limits.
Laura Elisa Valle Rios synthesized off-stoichiometric CZTSe powder samples by solid state reaction and studied the structural and chemical properties. Here she applied different analytical methods using also the HZB's large scale facilities BESSY II and BER II. Moreover she performed experiments at the Spallation Neutron Source (SNS) in Oakridge (US). With the results she obtained from complementary neutron and synchrotron X-ray diffraction experiments she was able to prove that CZTS can accomodate deviations from stoichiometry without collapse of the kesterite type structure by the formation of certain point defects. Laura Elisa could show correlations between chemical composition of the kesterite type semiconductor and intrinsic point defects and defect concentrations. Thus the crystal structure of CZTS can self-adapt to Cu-poor/Zn-rich and Cu-rich/Zn-poor compositions without any structural changes except in terms of the cation distribution.
Laura Elisa Valle Rios works at the HZB (EM-AKR) as a PhD student in the EU-funded Marie-Curie Initial Training Network KESTCELLS (Training for sustainable low cost PV technologies: development of kesterite based efficient solar cells). She is enrolled at the Freie Universtaet Berlin in the joint graduate school "Materials for Solar Energy Conversion" (MatSEC).
- Innovative battery electrode made from tin foamMetal-based electrodes in lithium-ion batteries promise significantly higher capacities than conventional graphite electrodes. Unfortunately, they degrade due to mechanical stress during charging and discharging cycles. A team at HZB has now shown that a highly porous tin foam is much better at absorbing mechanical stress during charging cycles. This makes tin foam an interesting material for lithium batteries.
- Perovskite solar cells: thermal stress is the key to their long term stabilityPerovskite solar cells are highly efficient and low cost in production. However, they still lack stability over the decades under real weather conditions. An international research collaboration led by Prof. Antonio Abate has now published a perspective on this topic in the journal Nature Reviews Materials. They explored the effects of multiple thermal cycles on microstructures and interactions between different layers of perovskite solar cells. They conclude that thermal stress is the decisive factor in the degradation of metal-halide perovskites. Based on this, they derive the most promising strategies to increase the long-term stability of perovskite solar cells.
- Leading Sasol scientist appointed as Industrial Research Fellow at HZBWithin the CARE-O-SENE project, HZB is cooperating with the South African company Sasol on innovative catalysts for sustainable aviation fuels (SAF). Now, the collaboration is intensifying: Dr. Denzil Moodley, a leading scientist in the field of Fischer-Tropsch at Sasol Research and Technology, is being appointed as Industrial Research Fellow at HZB. Moodley will contribute his expertise at HZB with the aim of accelerating the innovation cycle for sustainable fuel technologies.