HZB Newsroom

A team from HZB and the Fraunhofer Institute for Material and Beam Technology (IWS) in Dresden has gained new insights into lithium-sulphur pouch cells at the BAMline of BESSY II. Supplemented by analyses in the HZB imaging laboratory and further measurements, a new picture emerges of processes that limit the performance and lifespan of this industrially relevant battery type. The study has been published in the prestigious journal Advanced Energy Materials.

Iridium-based catalysts are needed to produce hydrogen using water electrolysis. Now, a team at HZB has shown that the newly developed P2X catalyst, which requires only a quarter of the Iridium, is as efficient and stable over time as the best commercial catalyst. Measurements at the EMIL lab at BESSY II have now revealed how the special chemical environment in the P2X catalyst during electrolysis promotes the oxygen evolution reaction during water splitting.

38,000 visitors in 20 years: high demand shows need for science education

Twenty years ago, on 29 November 2004, Klaus Böger, then Senator for Education in Berlin, opened one of the capital's first school laboratories. Since then, Helmholtz-Zentrum Berlin (HZB), in cooperation with the Berlin Senate, has successfully promoted science education through project days and further training in the school lab.

New cathode materials are being developed to further increase the capacity of lithium batteries. Multilayer lithium-rich transition metal oxides (LRTMOs) offer particularly high energy density. However, their capacity decreases with each charging cycle due to structural and chemical changes. Using X-ray methods at BESSY II, teams from several Chinese research institutions have now investigated these changes for the first time with highest precision: at the unique X-ray microscope, they were able to observe morphological and structural developments on the nanometre scale and also clarify chemical changes.

Bio-based thermoplastics are produced from renewable organic materials and can be recycled after use. Their resilience can be improved by blending bio-based thermoplastics with other thermoplastics. However, the interface between the materials in these blends sometimes requires enhancement to achieve optimal properties. A team from the Eindhoven University of Technology in the Netherlands has now investigated at BESSY II how a new process enables thermoplastic blends with a high interfacial strength to be made from two base materials: Images taken at the new nano station of the IRIS beamline showed that nanocrystalline layers form during the process, which increase material performance.

A team from the Technical University of Berlin, HZB, IMTEK (University of Freiburg) and Siemens Energy has developed a highly efficient alkaline membrane electrolyser that approaches the performance of established PEM electrolysers. What makes this achievement remarkable is the use of inexpensive nickel compounds for the anode catalyst, replacing costly and rare iridium. At BESSY II, the team was able to elucidate the catalytic processes in detail using operando measurements, and a theory team (USA, Singapore) provided a consistent molecular description. In Freiburg, prototype cells were built using a new coating process and tested in operation. The results have been published in the prestigious journal Nature Catalysis.

Ten teams at Helmholtz-Zentrum Berlin are building a long-term international alliance to converge practices and develop reproducibility and comparability in perovskite materials. The TEAM PV project is funded by the Federal Ministry of Education and Research (BMBF), Germany.

At HZB, 117 postdocs from 29 countries are employed. They play a crucial role in driving the main research activities, fostering creativity and innovation. To honor them, the Postdoc Appreciation Week was first organised in the USA in 2009 and has in the meantime become a regular event in Germany as well in the third week of September every year.

The MXene class of materials has many talents. An international team led by HZB chemist Michelle Browne has now demonstrated that MXenes, properly functionalised, are excellent catalysts for the oxygen evolution reaction in electrolytic water splitting. They are more stable and efficient than the best metal oxide catalysts currently available. The team is now extensively characterising these MXene catalysts for water splitting at the Berlin X-ray source BESSY II and Soleil Synchrotron in France.

Hydrogen can be produced via the electrolytic splitting of water. One option here is the use of photoelectrodes that convert sunlight into voltage for electrolysis in so called photoelectrochemical cells (PEC cells). A research team at HZB has now shown that the efficiency of PEC cells can be significantly increased under pressure.

At first glance, the plan sounds compelling: invent and develop future electrolysers capable of producing hydrogen directly from unpurified seawater. But a closer look reveals that such direct seawater electrolysers would require years of high-end research. And what is more: DSE electrolyzers are not even necessary - a simple desalination process is sufficient to prepare seawater for conventional electrolyzers. In a commentary in Joule, international experts compare the costs and benefits of the different approaches and come to a clear recommendation.

When biomass is converted into biodiesel, huge amounts of glycerol are produced as a by-product. So far, however, this by-product has been little utilised, even though it could be processed into more valuable chemicals through oxidation in photoelectrochemical reactors. The reason for this: low efficiency and selectivity. A team led by Dr Marco Favaro from the Institute for Solar Fuels at HZB has now investigated the influence of electrolytes on the efficiency of the glycerol oxidation reaction. The results can help to develop more efficient and environmentally friendly production processes.

On June 17, 2024, the Helmholtz Institute for Polymers in Energy Applications (HIPOLE Jena) was officially inaugurated in Jena in the presence of Wolfgang Tiefensee, Minister for Economy, Science, and Digital Society of the Free State of Thuringia. The institute was founded by the Helmholtz Center Berlin for Materials and Energy (HZB) in cooperation with the Friedrich Schiller University Jena. It is dedicated to developing sustainable polymer materials for energy technologies, which are expected to play a key role in the energy transition and support Germany’s goal of becoming climate-neutral by 2045.

 

HZB has launched a new recruiting film to attract talented people from administration, IT and technology. In cooperation with an external film company, our HR department has produced a video with a lot of commitment and creativity that presents the unique opportunities and team spirit at our centre.

The President of Chile, Gabriel Boric Font, visited HZB on 11 June with a delegation of 50 people. Among the highlights of the evening were the signing of a Memorandum of Understanding between the Chilean Corporation for the Promotion of Production (CORFO) and HZB and a visit to BESSY II light source.

Indium phosphide is a versatile semiconductor. The material can be used for solar cells, for hydrogen production and even for quantum computers – and with record-breaking efficiency. However, little research has been conducted into what happens on its surface. Researchers have now closed this gap and used ultra-fast lasers to scrutinise the dynamics of the electrons in the material.

Inorganic perovskite solar cells made of CsPbI₃ are stable over the long term and achieve good efficiencies. A team led by Prof. Antonio Abate has now analysed surfaces and interfaces of CsPbI₃ films, produced under different conditions, at BESSY II. The results show that annealing in ambient air does not have an adverse effect on the optoelectronic properties of the semiconductor film, but actually results in fewer defects. This could further simplify the mass production of inorganic perovskite solar cells.

An improved charging protocol might help lithium-ion batteries to last much longer. Charging with a high-frequency pulsed current reduces ageing effects, an international team demonstrated. The study was led by Philipp Adelhelm (HZB and Humboldt University) in collaboration with teams from the Technical University of Berlin and Aalborg University in Denmark. Experiments at the X-ray source BESSY II were particularly revealing.

The interactions between phosphoric acid and the platinum catalyst in high-temperature PEM fuel cells are more complex than previously assumed. Experiments at BESSY II with tender X-rays have decoded the multiple oxidation processes at the platinum-electrolyte interface. The results indicate that variations in humidity can influence some of these processes in order to increase the lifetime and efficiency of fuel cells. 

An HZB physicist has developed a new method for the comprehensive characterisation of semiconductors in a single measurement. The "Constant Light-Induced Magneto-Transport (CLIMAT)" is based on the Hall effect and allows to record 14 different parameters of transport properties of negative and positive charge carriers. The method was tested now on twelve different semiconductor materials and will save valuable time in assessing new materials for optoelectronic applications such as solar cells.

Since 2017, the German Cyclists' Federation (ADFC) has been awarding the EU-wide "Bicycle-Friendly Employer" certification. The Helmholtz-Zentrum Berlin has now been awarded the coveted silver seal. With this, the HZB wants to be even more attractive as an employer, especially for international applicants.

Sodium-ion batteries still have a number of weaknesses that could be remedied by optimising the battery materials. One possibility is to dope the cathode material with foreign elements. A team from HZB and Humboldt-Universität zu Berlin has now investigated the effects of doping with Scandium and Magnesium. The scientists collected data at the X-ray sources BESSY II, PETRA III, and SOLARIS to get a complete picture and uncovered two competing mechanisms that determine the stability of the cathodes.

The new HZB magazine lichtblick is out! Topics are: green hydrogen, construction projects and green construction for Ukraine, ... We invite you to browse through the online edition.

Yan Lu is appointed new Professor of Hybrid Materials for Electrochemical Energy Storage and Conversion at Friedrich Schiller University Jena together with HZB. Congratulations!

The production of green hydrogen requires catalysts that control the process of splitting water into oxygen and hydrogen. However, the structure of the catalyst changes under electrical tension, which also influences the catalytic activity. A team from the universities of Duisburg-Essen and Twente has investigated at BESSY II and elsewhere how the transformation of surfaces in perovskite oxide catalysts controls the activity of the oxygen evolution reaction. 

Anodes for the electrolytic splitting of water are usually iridium-based materials. In order to increase the stability of the iridium catalyst, a team at HZB and a group at HI-ERN have now produced a so-called material library: a sample in which the concentration of iridium and titanium oxides is systematically varied. Analyses of the individual sample segments at BESSY II in the EMIL laboratory showed that the presence of titanium oxides can increase the stability of the iridium catalyst significantly.

Many enzymes promise to break down plastic. But what works well in the lab often fails on a large scale. Now a new study by Gert Weber, HZB, Uwe Bornscheuer, University of Greifswald, and Alain Marty, Chief Scientific Officer of Carbios, shows how raising the bar for laboratory experiments could help identify promising approaches more quickly. The team demonstrated the new standards on four newly discovered enzymes.

It really is a problem: Microplastics are everywhere. Now, an HZB and University Potsdam team developed a method that for the first time enables us to precisely localise microplastics in soil. The combined 3D tomographies by neutrons and X-rays show exactly the location of particles and structural changes that can affect water flows and soil properties.

HZB is aware of its social responsibility. Now, HZB’s Greenhouse Gas Report is here, after being externally verified, and identifies the main sources of emissions. The report provides the basis for significantly reducing greenhouse gas emissions.

On Thursday, 12 October 2023, Michelle Browne received a prestigious award in Hamburg: The "Curious Mind Award" in the category "Mobility, Energy and Sustainable Business" by manager magazin. 

The first high-level event of the Green Deal Ukraina (GDU) project took place in October in Kyiv, Ukraine, attended by more than 150 participants. This first gathering and formal launch took place at an important moment: EU will share a new report on the countries progress towards EU and Ukraine will respond by sharing its own analysis, called pre-screening.

It sounds like magic: photoelectrodes could convert the greenhouse gas CO₂ back into methanol or N2 molecules into valuable fertiliser – using only the energy of sunlight. An HZB study has now shown that diamond materials are in principle suitable for such photoelectrodes. By combining X-ray spectroscopic techniques at BESSY II with other measurement methods, Tristan Petit’s team has succeeded for the first time in precisely tracking which processes are excited by light as well as the crucial role of the surface of the diamond materials.

A multidisciplinary team from Helmholtz-Zentrum Berlin (HZB) and Forschungszentrum Jülich (FZJ) is researching and improving novel tandem solar cells in order to bring them into application. For their approach and research achievements, Steve Albrecht, Antonio Abate and Eva Unger from HZB and Michael Saliba from FZJ received the High Impact Award on 27 September 2023. With the award, which comes with 50,000 euros in prize money, the Helmholtz Association and the Donors’ Association for the Promotion of Sciences and Humanities in Germany honour innovative approaches that have the potential to act as game-changers.

In theory, metal oxides are ideally suited as photoelectrodes for the direct generation of hydrogen with sunlight. Now, for the first time, a team at Helmholtz-Zentrum Berlin has succeeded in determining the transport properties of the charge carriers in different metal oxides over a time range of nine orders of magnitude.

The world's best tandem solar cells, consisting of a silicon bottom cell and a perovskite top cell, can today convert around one-third of incident solar radiation into electrical energy. These are record values, especially for a potentially very low-cost technology. A team at HZB is now providing the scientific data for the first time and describing how this development was achieved in the renowned journal Science. 

Photoelectrolysers and electrolysis cells can produce green hydrogen or fossil-free carbon compounds – but they require ion-exchange membranes. An HZB team has now studied the transport of ions through the membrane in a hybrid liquid gas electrolyzer at the X-ray source BESSY II. Contrary to expectations, however, concentration differences hardly drive electric field ions. Diffusion is therefore the decisive process. This finding could help in the development of highly efficient and significantly more environmentally friendly membrane materials.

Friedrich Schiller University Jena and the Helmholtz-Zentrum Berlin (Helmholtz Centre for Materials and Energy, HZB) will jointly establish the "Helmholtz Institute for Polymers in Energy Applications" (HIPOLE) on 1 July 2023. The aim of HIPOLE is to develop sustainable polymer materials for energy technologies that can be rapidly brought into application, in particular polymer-based batteries and perovskite solar cells with polymer additives. HIPOLE will be funded with up to 5.5 million euros per year by the Federal Ministry of Education and Research (BMBF, 90%) and the Free State of Thuringia (10%). In the start-up phase until 2028, the Free State of Thuringia will additionally fund the new institute with more than ten million euros and take over the financing of the construction costs for the laboratories and offices.

e will open our doors for the Long Night of the Sciences. Get exciting insights into our energy research, visit laboratories and ask us your questions about the energy transition. Our school lab invites you to take part in hands-on experiments - and a science show will keep you pumped up and amazed! Please bring your identity card!     

Green Deal Ukraina, funded by the German Federal Ministry of Education and Research, is working with partner institutions in Ukraine and Poland to establish an energy and climate think tank in the capital, Kiev. The aim is to provide independent and evidence-based advice on rebuilding a sustainable energy system in Ukraine. After all, the implementation of energy and climate legislation is a prerequisite for Ukraine's accession to the EU. The project started on 1 June 2023 and will run for four years.

Charlotte Klar and Katharina Austermann (both 18) have already come a long way: With their experiments on pyrolytic graphite, they are trying to solve a puzzle they found in the technical literature on diamagnetism. With their work, they convinced both the Jugend-forscht-Jury at the Berlin South Regional Competition and the Berlin Competition. Now, they will join the national competition which will take place from 18 to 21 May in Bremen.

Prof. Dr. Jens Eisert heads the Quantum Computation and Simulation research group, which is jointly funded by Freie Universität Berlin and HZB. The theoretical physicist recently received an Advanced Grant from the European Research Council ERC for his research project "DebuQC". But Eisert is not only an award-winning scientist, he is also concerned about global warming. Last year, on the initiative of Ryan Sweke, he and his team published a proposal that deserves attention: scientific publications on theoretical physics or chemistry could include a simple table listing the greenhouse gases emitted during the research. This would raise awareness of the fact that research is not climate neutral.

Dr. Wenxi Wang is working in the team of Prof. Yan Lu as Humboldt Foundation postdoctoral fellow. He studied at the Southern University of Science and Technology in Shenzhen, China, and completed his doctorate at the King Abdullah University of Science and Technology in Saudi Arabia. He specialises in the precise design of organic electrodes for lithium-sulfur and zinc-ion batteries and the investigation of the interactions between ions and active materials.

The greenhouse gas carbon dioxide can be converted into useful hydrocarbons by electrolysis. The design of the electrolysis cell is crucial in this process. The so-called zero-gap cell is particularly suitable for industrial processes. But there are still problems: The cathodes clog up quickly. At the HZB, Matthew Mayer and his team has now investigated what causes this and how this undesirable process can be prevented.

Lighter, more flexible and adaptable – the innovation platform Solar TAP develops innovative solutions for photovoltaic applications. The aim is to make surfaces already used in agriculture, the building sector and transport additionally usable for the expansion of solar energy with printed solar cells.

Cocoa beans can absorb toxic heavy metals such as cadmium from the soil. Some cultivation areas, especially in South America, are polluted with these heavy metals, in some cases considerably. In combining different X-ray fluorescence techniques, a team at BESSY II has now been able to non-invasively measure for the first time where cadmium accumulates exactly in cocoa beans: Mainly in the shell. Further investigations show that the processing of the cocoa beans can have a great influence on the concentration of heavy metals.

Solid-state Lithium-Sulfur batteries offer the potential for much higher energy densities and increased safety, compared to conventional lithium-ion batteries. However, the performance of solid-state batteries is currently lacking, with slow charging and discharging being one of the primary causes. Now, a new study from HZB shows that sluggish lithium ion transport within a composite cathode is the cause of this slow charging and discharging.

The energy transition presents us all with major challenges. We need not only electricity from renewable sources, but also storage solutions. At the Wannsee site, Yan Lu's team is researching novel lithium-sulphur batteries that can store much more energy than conventional batteries. The laboratory is unique in the Berlin-Brandenburg research landscape. In the cover story, the head of department tells us what motivates her about her work.

Sunlight can be used to produce green hydrogen directly from water in photoelectrochemical (PEC) cells. So far, systems based on this "direct approach" have not been energetically competitive. However, the balance changes as soon as some of the hydrogen in such PEC cells is used in-situ for a catalytic hydrogenation reaction, resulting in the co-production of chemicals used in the chemical and pharmaceutical industries. The energy payback time of photoelectrochemical "green" hydrogen production can be reduced dramatically, the study shows.

MXenes are able to store large amounts of electrical energy like batteries and to charge and discharge rather quickly like a supercapacitor. They combine both talents and thus are a very interesting class of materials for energy storage. The material is structured like a kind of puff pastry, with the MXene layers separated by thin water films. A team at HZB has now investigated how protons migrate in the water films confined between the layers of the material and enable charge transport. Their results have been published in the renowned journal Nature Communications and may accelerate the optimisation of these kinds of energy storage materials.

Dr. Artem Musiienko has earned a prestigious Maria Skłodowska Curie Postdoctoral Fellowship for his research project HyPerGreen. In the group of Prof. Antonio Abate, HZB, Musiienko will explore and improve lead-free perovskite solar cells with the goal to increase their efficiency to more than 20 %.  

Manfred Weiss, Sebastian Fiechter, Annette Pietzsch and Michael Tovar have been available to you as ombudspersons since 1 January 2023. They will be happy to advise you on all questions regarding good scientific practice at the HZB.

The current world record of tandem solar cells consisting of a silicon bottom cell and a perovskite top cell is once again at HZB. The new tandem solar cell converts 32.5 % of the incident solar radiation into electrical energy. The certifying institute European Solar Test Installation (ESTI) in Italy measured the tandem cell and officially confirmed this value which is also included in the NREL chart of solar cell technologies, maintained by the National Renewable Energy Lab, USA.

In order to transfer tandem solar cells from laboratory scale to production, HZB is cooperating with the solar module manufacturer Meyer Burger, which has great expertise in heterojunction technology (HJT) for silicon modules. Within the framework of this cooperation, mass production-ready silicon bottom cells based on heterojunction technology are to be combined with a top cell based on perovskite technology.

On Tuesday, 6 December 2022, Dr. Eike Köhnen received the Tiburtius Prize (First Place) for outstanding dissertations. Eike Köhnen has contributed to significantly increasing the efficiency of tandem solar cells made of perovskite and silicon, to the point of setting world records.

At the end of October 2022, the management appointed Ana Sofia Anselmo and Silvia Zerbe as new diversity officers. Together they will address diversity at HZB and drive it forward with employees. Ana works in the Director’s Office and is responsible for International Affairs. Silvia is deputy press spokesperson at HZB and is dedicated to internal communication at the centre.

Nanodiamond materials have potential as low-cost photocatalysts. But until now, such carbon nanoparticles required high-energy UV light to become active. The DIACAT consortium has therefore produced and analysed variations of nanodiamond materials. The work shows: If the surface of the nanoparticles is occupied by sufficient hydrogen atoms, even the weaker energy of blue sunlight is sufficient for excitation. Future photocatalysts based on nanodiamonds might be able to convert CO₂ or N₂ into hydrocarbons or ammonia with sunlight.

PEPPERONI, a four-year Research and Innovation project co-funded under Horizon Europe and jointly coordinated by Helmholtz-Zentrum Berlin and Qcells, will support Europe in reaching its renewable energy target of climate neutrality by 2050. The project will help advance perovskite/silicon tandem photovoltaics (PV) technology’s journey towards market introduction and mass manufacturing.

Photoelectrodes based on BiVO₄ are considered top candidates for solar hydrogen production. But what exactly happens when they come into contact with water molecules? A study in the Journal of the American Chemical Society has now partially answered this crucial question:  Excess electrons from dopants or defects aid the dissociation of water which in turn stabilizes so-called polarons at the surface. This is shown by data from experiments conducted at the Advanced Light Source at Lawrence Berkeley National Laboratory. These insights might foster a knowledge-based design of better photoanodes for green hydrogen production.

Certain metal oxides are considered good candidates for photocatalysts to produce green hydrogen with sunlight. A Chinese team has now published exciting results on copper(I) oxide particles in Nature, to which a method developed at HZB contributed significantly. Transient surface photovoltage spectroscopy showed that positive charge carriers on surfaces are trapped by defects in the course of microseconds. The results provide clues to increase the efficiency of photocatalysts.

Tandem solar cells, which combine two different perovskite semiconductors, promise high efficiencies and can be produced with very little energy input. Such modules could even be bendable. Together with partners from industry and research, HZB expert Prof. Steve Albrecht is working to realise this vision. His team recently succeeded in producing an all-perovskite tandem solar cell with a certified efficiency of 27.2 %. A conversation about the opportunities and challenges of the perovskite-perovskite technology.

The international research project CARE-O-SENE (Catalyst Research for Sustainable Kerosene) was granted 30 million euros in funding by the German Federal Ministry of Education and Research (BMBF). Additionally, the industrial consortium partners contribute 10 million euros. The aim of the project is to develop novel, next-generation Fischer-Tropsch catalysts and thus to optimise the production of sustainable kerosene – or Sustainable Aviation Fuel (SAF) – on an industrial scale. Helmholtz-Zentrum Berlin (HZB) is part of this collaboration.

At HZB, a laboratory for automated X-ray tomography on solid-state batteries is being set up. The special feature: 3D data during charge/discharge processes (operando) can be evaluated quickly and in a more versatile way using artificial intelligence (AI) methods. The Federal Ministry of Research and Education is funding the "TomoFestBattLab" project with 1.86 million euros.

In order to produce green hydrogen, water can be split up via electrocatalysis, powered by renewable sources such as sun or wind. A review article in the journal Angewandte Chemie Int. Ed. shows how modern X-ray sources such as BESSY II can advance the development of suitable electrocatalysts. In particular, X-ray absorption spectroscopy can be used to determine the active states of catalytically active materials for the oxygen evolution reaction. This is an important contribution to developing efficient catalysts from inexpensive and widely available elements.

The non-university research institutions in Berlin will work even more closely together in the future. Their association Berlin Research 50 (BR50), founded in 2020, has joined forces to form a registered non-profit association on 4. October 2022. Together, the research institutions want to further develop and strengthen Berlin as a science location.

Wie umgehen mit begrenztem Platz? Städte und Kommunen müssen sich jetzt auf die Folgen des Klimawandels vorbereiten. Gründächer, begrünte Fassaden und großflächige Entsiegelungen könnten zu einem besseren Mikroklima beitragen. Aber wird der Platz nicht auch für Photovoltaik benötigt?

In einem kontroversen Gespräch loten die Experten Björn Rau (HZB, BAIP) und Jens Hasse (Deutsches Institut für Urbanistik) die Optionen aus und finden neue Lösungen.

Dr. Michelle Browne establishes her own young investigator group at the HZB . Starting in August, the group is co-funded by the Helmholtz Association for the next five years. The electrochemist from Ireland concentrates on electrolytically active novel material systems and wants to develop next-generation electrocatalysts, for example hydrogen production. At HZB she will find the perfect environment to conduct her research.

Industrial processes always produce fine-grained residues. These rarely find their way back into the industrial value chain, but are usually disposed of and represent a potential environmental risk. The FINEST project records and investigates various of these fine-grained material flows with the aim of developing new concepts to keep them in the cycle and safely dispose of remaining residues. 
FINEST was successful in the Helmholtz Association's sustainability competition and will now receive 5 million euros in funding. 

Solar photovoltaics is a reliable and sustainable way to generate energy. A study has evaluated for the first time the lifecycle environmental impact of industrially produced perovskite-on-silicon tandem solar modules, provided by Oxford PV. The conclusion: these innovative tandem solar modules are even more environmentally friendly than conventional silicon heterojunction modules over their lifetimes. The study has now been published by the peer reviewed journal Sustainable Energy & Fuels.

Important info: At the HZB, FFP2 masks are mandatory indoors from the age of 14 during this event.

How can solar cells be produced even more efficiently? Why is "green" hydrogen so important for our future? Why does Berlin need an accelerator to screen materials? The answers are available at the Long Night of the Sciences. On July 2, 2022, 5 p.m. to midnight, HZB opens its doors at the Adlershof site and invites young and old to experiment.

Teams from Helmholtz-Zentrum Berlin (HZB) and University College London (UCL) have visualised the water distribution in a fuel cell in three dimensions and in real time for the first time by evaluating neutron data from the Berlin Experimental Reactor shut down in 2019. The analysis opens new possibilities for more efficient and thus more cost-effective fuel cells.

People from many different countries work at the Helmholtz-Zentrum Berlin and enrich our atmosphere. For our cookbook, employees and guest researchers from six continents have contributed their favorite recipes.

JOHANNESBURG, SOUTH AFRICA – 24 May 2022: CARE-O-SENE research project will develop advanced catalysts for sustainable aviation fuels

The company Sasol and Helmholtz-Zentrum Berlin (HZB) will lead a consortium to develop and optimise next-generation catalysts that will play a key role in decarbonising the aviation sector through sustainable aviation fuels (SAF).

In order to explain the particularly favourable properties of perovskite semiconductors for solar cells, various hypotheses are circulating. Polarons or a giant Rashba effect, for example, are thought to play a major role. A team at BESSY II has now experimentally disproved these hypotheses. In doing so, they further narrow down the possible causes for the transport properties and enable better approaches for the targeted optimisation of this class of materials.

Producing low-cost metal-oxide thin films with high electronic quality for solar water splitting is not an easy task. Especially since quality improvements of the upper metal oxide thin films need thermal processing at high temperatures, which would melt the underlying glass substrate. Now, a team at HZB-Institute for Solar Fuels has solved this dilemma: A high intensity and rapid light pulse directly heats the semiconducting metal-oxide thin film, allowing to achieve the optimal heating conditions without damaging the substrate.

HZB is an employer that comprehensively strengthens and cares for the diversity of its employees. HZB publicly acknowledges this by signing the Diversity Charter. The charter is run by an association that works to anchor diversity in the working world.

The BAIP consulting office for building-integrated photovoltaics has been launched as a knowledge transfer project in 2019, funded by the Helmholtz Association's Initiative and Networking Fund. In order to build a bridge between the world of construction and photovoltaics, the consulting office provides comprehensive knowledge for architects, planners, builder-owners, investors and urban developers. After an excellent evaluation, the BAIP consulting office will be permanently financed by HZB.

Q CELLS and Helmholtz-Zentrum Berlin achieve a new world record efficiency for a 2-terminal tandem solar cell combining a mass-production ready silicon bottom cell based on Q.ANTUM technology and a top-cell based on perovskite technology. The efficiency is 28.7%.

Many semiconducting materials are possible candidates for solar cells. In recent years, perovskite semiconductors in particular have attracted attention, as they are both inexpensive and easy to process and enable high efficiencies. Now a study with 15 participating research institutions shows how terahertz (TRTS) and microwave spectroscopy (TRMC) can be used to reliably determine the mobility and lifetime of the charge carriers in new semiconducting materials. Using these measurement data it is possible to predict the potential efficiency of the solar cell in advance and to classify the losses in the finished cell.  

So-called PERC cells are used in mass production of silicon solar cells, they are considered the workhorses of photovoltaics, dominating the market. Now two teams from HZB and the Institute for Solar Energy Research in Hamelin (ISFH) have shown that such standard silicon cells are also suitable as a basis for tandem cells with perovskite top cells. Currently, the efficiency of the tandem cell is still below that of optimised PERC cells alone, but could be increased to up to 29.5% through targeted optimisation. The research was funded by the German Federal Ministry of Economics as part of a joint project.

On February 17, 2022, the Adlershof Dissertation Prize was awarded for the 20th time. Dr. Amran Al-Ashouri (3rd from right) from the HZB young investigator research group "Perovskite tandem solar cells" received the prize endowed with 3,000 euros. The physicist is researching how new organic contact layers can be used to optimize highly efficient perovskite silicon tandem solar cells.

Lithium-sulphur (Li/S) batteries have significantly higher energy densities than conventional lithium-ion batteries, but age very quickly. Now, for the first time, a team at HZB has investigated Li/S batteries in the industry-relevant pouch cell format with different electrolytes during operation. Teams from TU Dresden and the Fraunhofer IWS were also involved in the study. With a specially developed measuring cell, impedance, temperature and pressure can be recorded at different times and combined with radiographic images. The evaluation shows how the electrolyte affects the formation of unwanted sulphur particles and polysulphides. The study has been published in the renowned journal Advanced Energy Materials.

Highly efficient (electro-)catalysts are essential for the production of green hydrogen, the chemical industry, fertiliser production and other sectors of the economy. In addition to transition metals, a variety of other metallic or non-metallic elements have now moved into the focus of research. In a review article, experts from CatLab and Technische Universität Berlin present an overview on current knowledge and a perspective on future research questions.

To support the development of young scientists at HZB in the best possible way - this has been a long-standing goal of the HZB. Now this task will be pursued even more strategically. To this end, the new board “HZB Succeed” has been founded in January 2022.

Turning a scientific question into a product is the requirement that the winners of the HZB Technology Transfer Prize should fulfil. The team led by Tobias Henschel, Bernd Stannowski and Sebastian Neubert won more than just a prize.

An international team of experts has collected data on metal halide perovskite solar cells from more than 15,000 publications and developed a database with visualisation options and analysis tools. The database is open source and provides an overview of the rapidly growing knowledge as well as the open questions in this exciting class of materials. The study was initiated by HZB scientist Dr. Eva Unger and implemented and coordinated by her postdoc Jesper Jacobsson.

Three HZB teams led by Prof. Christiane Becker, Prof. Bernd Stannowski and Prof. Steve Albrecht have jointly managed to increase the efficiency of perovskite silicon tandem solar cells fabricated completely at HZB to a new record value of 29.80 %. The value has now been officially certified and is documented in the NREL-charts. This brings the 30 percent mark within reach.

Which technical and nature-based options as well as political decisions can support Germany in being CO2-neutral? These questions are answered by the new web atlas of the Climate Service Center Germany (GERICS) at the Helmholtz-Zentrum Hereon. The new tool is aimed at politicians, experts and the public. The HZB has also contributed to the web atlas.

In mechanochemistry, reagents are finely ground and mixed so that they combine to form the desired product, even without need for solvent. By eliminating solvent, this technology promises to contribute significantly towards ‘green’ and environmentally benign chemical manufacture in the future. However, there are still major gaps in understanding the key processes that occur during mechanical treatment and reaction. A team led by the Federal Institute for Materials Research (BAM) has now developed a method at BESSY II to observe these processes in situ with X-ray scattering. 

The Helmholtz-Zentrum Berlin (HZB) is the first non-university research institution to have undergone the Stifterverband's diversity audit "Vielfalt gestalten". The certification attests to the HZB's opportunity-oriented concepts and measures for diverse groups of people.

Dr. Olga Kasian is investigating why catalysts for hydrogen production by water electrolysis are limited in efficiency. The chemist has now accepted a professorship at the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU). The W2 professorship is entitled "Materials for Electrochemical Energy Conversion" and is located at the Faculty of Engineering.

An international team at HZB and Charles University Prague has investigated how charge carriers in so called MAPI-perovskite semiconductors interact with different defects. They show that a large proportion of defects quickly releases trapped charge carriers. These results could help to further improve the properties of perovskite solar cells.

On 26 September, not only the Bundestag but also the Berlin House of Representatives will be newly elected. In a position paper, the non-university institutions in the capital that are united in Berlin Research 50 now emphasise what is important for research after the election. In it, they outline 10 demands that the future Senate should implement in order to further strengthen Berlin as a science metropolis.

In the presence of the State Secretary for Economic Affairs, Energy and Operations of the State of Berlin, Christian Rickerts, the HZB officially commissioned the solar façade of a new research building on 6 September 2021. What makes it so special is that the elegant façade not only generates up to 50 kilowatts of electricity (peak power). It also provides important insights into the behaviour of the solar modules under different weather conditions.  

Metal-organic perovskite materials promise low-cost and high-performance solar cells. Now a group at HZB managed to de-couple the different effects of self-assembled monolayers of organic molecules (SAMs) that reduce losses at the interfaces. Their results help to optimise such functional interlayers.

At the end of 2019, the Berlin neutron source BER II was shut down as scheduled. To ensure that the high-quality instruments can continue to be used for research, they are moving to suitable neutron sources in Germany and abroad. Now, another move has been agreed upon: The Very Small Angle Scattering Instrument (VSANS) will find a new home at the Breazeale Research Reactor at Penn State University, USA, in spring 2022.

Crystalline cobalt arsenide is a catalyst that generates oxygen during electrolytic water splitting in the production of hydrogen. The material is considered to be a model system for an important group of catalysts whose performance increases under certain conditions in the course of electrolysis. Now a HZB-team headed by Marcel Risch has observed at BESSY II how two simultaneous mechanisms are responsible for this. The catalytic activity of the individual catalysis centres decreases in the course of electrolysis, but at the same time the morphology of the catalyst layer also changes. Under favourable conditions, considerably more catalysis centres come into contact with the electrolyte as a result, so that the overall performance of the catalyst increases.

A team from the Helmholtz-Zentrum Berlin, Ulm University, and Heidelberg University has now investigated how hydrogen can be produced at the South Pole using sunlight, and which method is the most promising. Their conclusion: in extremely cold regions, it can be considerably more efficient to attach the PV modules directly to the electrolyser, i.e. to thermally couple them. This is because the waste heat from the PV modules increases the efficiency of electrolysis in this environment. The results of this study, which has now been published in Energy & Environmental Science, are also relevant for other cold regions on Earth, such as Alaska, Canada, and high mountain regions, for example. In these places, solar hydrogen could replace fossil fuels such as oil and petrol.

The HZB is coordinating a major European collaborative project to open up new opportunities for the European solar industry. The VIPERLAB project involves 15 renowned research institutions from Europe, as well as Switzerland and Great Britain. It will be funded within the framework of the EU's Horizon 2020 programme for the next three and a half years with a total of 5.5 million euros, from which the HZB will receive just under 840,000 euros. 

Using small-angle scattering at the PTB X-ray beamline of BESSY II, an HZB team was able to experimentally investigate the colloidal chemistry of perovskite precursor solutions used for solar cell production. The results contribute to the targeted and systematic optimization of the manufacturing process and quality of these exciting semiconductor materials.

Metal oxides such as rust are intriguing photoelectrode materials for the production of green hydrogen with sunlight. They are cheap and abundant, but in spite of decades of research, progress has been limited. A team at HZB, together with partners from Ben Gurion University and the Technion, Israel, has now analysed the optoelectronic properties of rust (haematite) and other metal oxides in unprecedented detail. Their results show that the maximum achievable efficiency of haematite electrodes is significantly lower than previously assumed. The study demonstrates ways to assess new photoelectrode materials more realistically.

Solar cells made of crystalline silicon achieve peak efficiencies, especially in combination with selective contacts made of amorphous silicon (a-Si:H). However, their efficiency is limited by losses in these contact layers. Now, for the first time, a team at Helmholtz-Zentrum Berlin (HZB) and the University of Utah, USA, has experimentally shown how such contact layers generate loss currents on the nanometre scale and what their physical origin is. Using a conductive atomic force microscope, they scanned the solar cell surfaces in ultra-high vacuum and detected tiny, nanometre-sized channels for the detrimental dark currents, which are due to disorder in the a-Si:H layer.

HZB has been certified as a family-friendly employer since 2011. Now the research centre has successfully completed the re-auditing process and developed further measures to promote a life phase conscious working culture. The certificate is considered a seal of quality for the company's compatibility policy and is awarded by the board of trustees of berufundfamilie Service GmbH.

The HZB “DR coordination” is now the HZB Graduate Center. Since the beginning of 2018, the DR coordination has been continuously expanding the offers and standards at the HZB for doctoral researchers and their advisors. The ideas and suggestions that were collected in discussions with numerous stakeholders and in various HZB committees on this topic are leading the path and are incorporated in the set up of a uniform HZB-wide umbrella structure for doctoral researchers and their advisors - the HZB Graduate Center.

Photoanodes made of metal oxides are considered to be a viable solution for the production of hydrogen with sunlight. α-SnWO₄ has optimal electronic properties for photoelectrochemical water splitting with sunlight, but corrodes easily. Protective layers of nickel oxide prevent corrosion, but reduce the photovoltage and limit the efficiency. Now a team at HZB has investigated at BESSY II what happens at the interface between the photoanode and the protective layer. Combined with theoretical methods, the measurement data reveal the presence of an oxide layer that impairs the efficiency of the photoanode.

Helmholtz-Zentrum Berlin (HZB) and Humboldt-Universität zu Berlin (HU) have signed a cooperation agreement with the aim of establishing a joint research laboratory for catalysis in the IRIS research building of HU in Adlershof. The IRIS research building offers optimal conditions for the research and development of complex material systems.

An HZB team has published a report in the journal Science on the development of its current world record of 29.15% efficiency for a tandem solar cell made of perovskite and silicon. The tandem cell provided stable performance for 300 hours – even without encapsulation. To accomplish this, the group headed by Prof. Steve Albrecht investigated physical processes at the interfaces to improve the transport of the charge carriers.

An innovative laboratory and office building for catalysis research will be built in Berlin-Adlershof: CatLab is to become an international beacon for catalysis research and drive forward the development of novel catalyst materials, which are urgently required for the production of green hydrogen for the energy transition. In an architectural competition four winning designs have now been selected. All designs include climate friendly solutions.

For the production of high-quality metal-halide perovskite thin-films for large area photovoltaic modules often optimized inks are used which contain a mixture of solvents. An HZB team at BESSY II has now analysed the crystallisation processes within such mixtures. A model has also been developed to assess the kinetics of the crystallisation processes for different solvent mixtures. The results are of high importance for the further development of perovskite inks for industrial-scale deposition processes of these semiconductors.

Hydrogen produced by using solar energy could contribute to a climate neutral energy system of the future. But there are hurdles on the way from laboratory scale to large-scale implementation. A team at HZB has now presented a method to visualise convection in the electrolyte and to reliably simulate it in advance with a multiphysics model. The results can support the design and scaling up of this technology and have been published in the renowned journal Energy and Environmental Science.

Scientists at HZB have printed and explored different compositions of caesium based halide perovskites (CsPb(Br_xI_1−x)₃ (0 ≤ x ≤ 1)). In a temperature range between room temperature and 300 Celsius, they observe structural phase transitions influencing the electronic properties. The study provides a quick and easy method to assess new compositions of perovskite materials in order to identify candidates for applications in thin film solar cells and optoelectronic devices.

Solar-modules shimmer bright blue on the cladding of a new building at the Helmholtz-Zentrum Berlin (HZB). They are special CIGS thin-film modules custom-developed and produced in Germany for integration into the building’s envelope. The solar cladding not only meets part of the power requirement, but is also a realistic laboratory in and of itself: an HZB team is monitoring the long-term behaviour of the modules under varying environmental conditions and evaluating the data. 

"I find it remarkable and encouraging that more and more citizens are joining the protests of the younger generation and calling for a turnaround for climate protection," says Prof. Bernd Rech, Scientific Director of the Helmholtz-Zentrum Berlin (HZB). In an open video message on the occasion of the worldwide climate day planned for Friday, he welcomes the fact that HZB staff members want to participate in the actions. At the same time he calls on people not to be afraid of technical changes. "The technologies for a climate-friendly energy supply are available. We must now use them quickly, but we must also improve them and create new options".

Since September 2020, the Helmholtz-Zentrum Berlin is again a member of IGAFA - the Initiative of Non-University Research Institutions in Adlershof. Prof. Dr. Jan Lüning, scientific director of the HZB, was elected to the association's board.

Dr. Tristan Petit has received a prestigious Starting Grant from the European Research Council for 1.5 million euros over the next five years. The materials researcher will use the grant to investigate a new class of materials known as MXenes for storing electrical energy. MXenes can store and deliver large amounts of electrical energy extremely quickly. They might play an important role in energy storage alongside batteries and supercapacitors. The ERC Starting Grant is one of the most important European research grants.

One of the most promising ways to increase the availability of solar energy is to convert excess production into hydrogen. The PECSYS project has investigated the best possible material and technology combinations to facilitate such an operation.

Im September veranstaltet die Beratungsstelle für bauwerkintegrierte Photovoltaik (BIPV) „BAIP“ zusammen mit der Architektenkammer Niedersachsen ein Seminar für Architekt*innen zum Thema Bauwerkintegrierte Photovoltaik: Architektur-Gestaltung und Ausführung

The Helmholtz-Zentrum Berlin (HZB) is launching a major new project through an interdisciplinary architectural competition: an innovative laboratory and office building for expanding joint catalysis research between the HZB and the Max Planck Society (MPS). Catlab is to become an international beacon for catalysis research that will advance the development of novel catalyst materials urgently needed for the energy transition.

The meadows are lush green, the ice saints (almost) over: Now is the perfect time for the sheep and goats to return from their winter quarters! Until late autumn, they will now graze the near-natural HZB campus in Wannsee and serve the natural preservation of the landscape - completely without a lawn mower.

On 14 May 2020, two charging points for electric cars were installed near the BESSY II main building. But not only the hybrid company car fleet is to be charged here. Soon, employees will also have the opportunity to charge their private cars at one of the charging points.

The promising halide perovskite materials for solar energy conversion show high efficiencies, but this comes at a cost: The best perovskite materials incorporate toxic lead which poses a hazard to the environment. To replace lead by less toxic elements is not easy since lead-free perovskites show lower stability and poor efficiencies. Now, an international collaboration has engineered a new hybrid perovskite material with promising efficiency and stability.

A special branch in the famous NREL-chart for solar cell world records refers to a newly developed tandem solar cell by HZB teams. The world-record cell combines the semiconductors perovskite and CIGS to a monolithic "two-terminal" tandem cell. Due to the thin-film technologies used, such tandem cells survive much longer in space and can even be produced on flexible films. The new tandem cell achieves a certified efficiency of 24.16 percent.

The situation in Berlin's doctors’ surgery is becoming increasingly acute due to the lack of important protective clothing and disinfectants. Some practices have already had to close for this reason. The HZB has therefore decided to provide quick help and is donating 65 boxes of protective clothing that are normally used for work in the laboratories and clean rooms. The boxes were handed over to the Kassenärztliche Vereinigung Berlin on 27.03.2020.

Two dimensional titanium carbides, so-called MXenes, are being discussed as candidates for the rapid storage of electrical energy. Like a battery,MXenes can store large amounts of electrical energy through electrochemical reactions- but unlike batteries,can be charged and discharged in a matter of seconds. In collaboration with Drexel University, a team at HZB showed that the intercalation of urea molecules between the MXene layers can increase the capacity of such "pseudo-capacitors" by more than 50 percent. At BESSY II they have analysed how changes of the MXene surface chemistry after urea intercalation are responsible for this.

Berlin als internationale Wissenschaftsmetropole zu stärken, ist Ziel einer gemeinsamen Initiative der außeruniversitären Forschungseinrichtungen der Hauptstadt. Sie haben sich zur BR 50 (Berlin Research 50) zusammengeschlossen, um künftig gemeinsam Strategien für die Forschung und den Austausch mit Politik und Gesellschaft zu entwickeln. Auch das Helmholtz-Zentrum Berlin hat sich der Initiative angeschlossen. Die Kooperation mit den Berliner Universitäten wird hierdurch erleichtert und verstärkt.

What is ultraviolet radiation? What are X-rays used for? And what is radioactivity again? These questions are on the curriculum in physics lessons, but vivid experiments on these topics are rare. From 5 to 13 March 2020, pupils can conduct experiments on these topics in the HZB's school laboratory in Berlin-Adlershof. The public is invited to attend on 12 March.

Lead from metal-organic perovskite compounds can be absorbed particularly easily by plants. The bioavailability is significantly higher than that of lead from inorganic compounds as found in batteries. This is shown in a study by HZB researcher Antonio Abate with partners in China and Italy, published in Nature communications.

Since 1 January 2020, HZB is drawing 100 per cent of its electricity from renewable energies. This reduces CO₂ emissions by around 17,400 tons per year (related to 2018). By switching to green electricity, HZB acknowledges its responsibility to contribute to climate protection.