The highly motivated and multidisciplinary crew at RL1 aims at significantly contributing in the global energy challenge. In particular, we strategically position our activities in advancing the next generation materials for renewable energy generation from the sun (solution processed efficient (>15%) photovoltaics) and from waste heat (emerging thermoelectrics with ZT values between 1 and 3) as well as storage technologies (post-Li-ion battery technologies with energy densities > 250 Wh/kg). The research so far has led to a good productivity in terms of papers and patents, with an additional success in receiving 3 ERC grants. 

In order to ensure long term viability and greater social impact, we place special emphasis on developing innovative sustainable technologies, where critical or toxic materials are replaced by others, in the field of metal organic frameworks, oxide-nitride layers, carbons and polymeric materials.

Importantly, at RL1 we tap into the many years of experience in advanced characterization and theoretical tools that the staff members have acquired in order to develop a fundamental understanding of materials for energy, e.g. XRD, AFM/SPM, TEM, IR, UV and Raman spectroscopies, as well as on a nearly free access to ALBA’s synchrotron lines. 

From this knowledge, general rules are derived, which enable the rational selection of suitable materials that should be further developed into higher technology readiness levels in the field of energy conversion and storage. We aim at challenging targets to be able to contribute to high impact publications as well as to industrial acceptance and further project activities, and to new conceptual devices that could merge different technologies, such as thermoelectrics and photovoltaics. One of our future goals is to get more involved with global players in this field, in Europe and the world, to increase the mobility of our young researchers and increase our overall impact.

In 2017, the Scientific Advisory Board evaluated the RL1. Here we summarize the 2017 main highlights and activities.

2017 MAIN HIGHLIGTS:

Photovoltaics: To enhance the energy conversion efficiency from light to electricity of organic photovoltaics (OPV) towards the 20 % goal, an ultrafast platform for the screening of the large library of organic materials has been developed within the ERC-FOREMAT, by coupling combinatorial samples with advanced spectroscopy. This fabrication platform can also be used to manufacture miniaturized spectrometers and polarization detectors. The full value chain in OPV will be further investigated in the H2020 ITN project SEPOMO. Moreover, the development of new scanning force tools that help to draw molecular-scale portraits of organic domains has also been achieved. Besides organics, other materials are being investigated for PV applications, including perovskites, boron-based, oxides, as well as nanostructured inorganics and hybrid systems. A transversal strategy for enhancing light harvesting in thin film PV is the use of photonic structures, which are also been fabricated through low cost up-scalable soft lithography techniques (ERC-ENLIGHTMENT).

Thermoelectrics: Organic materials have low thermal conductivities and high Seebeck coefficients. To allow the increasing amount of doping needed to enhance the electrical conductivity and simultaneously preventing mechanical failure, we have introduced the ternary blend concept, in which a commodity polymer acts as binder and thus enables truly bendable thermoelectric devices. We are also targeting the controlled doping of nanocarbon materials as they are very promising candidates for thermoelectrics. We are exploring novel polymer/carbon strategies and One 2017 granted FIP project is devoted to novel polymer/carbon nanotube strategies and the frontiers of thermal transport detection in nanostructures. In our attempt to take thermoelectrics towards higher TRLs, efforts are targeting the understanding of thermal interfaces, which play a key role in real life devices.

Batteries: The major focus is on development of sustainable post-lithium battery technologies based on abundant, non-toxic elements.  Besides optimization of hard carbon anodes for Na-ion batteries (H2020 project NAIADES), and study of discharge products in Na-air batteries by X-ray imaging, efforts are being directed at consolidating research in multivalent technologies based on elements enabling the transfer of more than one electron.  Within the framework of the ERC- CAMBAT, new electrolyte formulations enabling efficient deposition of Mg and Ca are being sought. Efforts to develop cathodes for Ca based batteries will be strengthened in the framework of the (FET-OPEN CARBAT) project. Finally, Zn-air batteries using aqueous electrolytes are revisited using a new cell concept.

Novel materials for alternative energy applications: A new family of bidimensional copper oxides produced hydrothermally show significant in plane ferromagnetism and electroactive properties and novel carbon/silica composite films show improved electrochemical sensing properties. Alternatively, processing of microporous metal organic frameworks (MOFs) using supercritical CO₂ is used, precisely, for CO₂ capture. Advanced spectroscopic characterization of highly-porous MOF particles that spontaneously assemble into well-ordered 3D superstructures enabled the design and of photonic crystals. Contributions in the field of hydrogen production have also been published during 2017 related to synchrotron X-ray investigation of TiO₂ interfaces for photocatalysis and the development of Au/TiO₂ lyogels for hydrogen production. Finally, alternative materials that could find diverse uses in the field of energy include decorated semiconducting quantum dots which exhibit kinetic fluorescence switching.

2017 ACTIVITIES:

During 2017, two new labs associated to RL1 have been completed through the funds obtained from two ERC grants (FOREMAT and ENLIGHTMENT). The first one consists on an assembly line for photovoltaic, thermoelectric and photonic devices, while the second contains a number of advanced tools for the characterization of photovoltaic, thermoelectric and structural properties. A third lab is being assembled for battery research associated to a third ERC grant (CAMBAT).

The scientific activities have resulted in many different contributions. A non-exhaustive list includes, over 60 papers published in high impact factor journals (including 1 Nat. Mater., 1 Nat. Chem., and 2 Adv. Mater.), 5 book chapters, more than 15 invited talks at international conferences, and several workshops organized (including one in emerging photovoltaics, and another on the structure-performance nexus at the MRS in Boston), 2 patents filed, several contracts with the private sector (including Repsol, Toyota and Eurecat), and 3 PhD defences (OTE/OPV, nitrides and oxide PV). In terms of individual recognition, we would like to highlight that two researchers have obtained permanent positions (tenured scientist) and will focus their activities on thermoelectrics and oxide photovoltaics, and another two have been promoted (from Tenured to Research scientist). One of our staff (M. Coll) has been awarded the L’Oréal-Unesco prize for Women in Science 2017.

Several measures are underway to follow the advice of the SAB with respect to strategic cooperation with neighbouring technological players. On the one hand, negotiations are in place with technological centres in Catalonia to sign a Memorandum of Understanding to help bringing novel materials to more advanced TRLs. On the other hand, we are participating in different advanced networks, such as ALISTORE in battery research, ITN SEPOMO on organic photovoltaics, one Networks of Excellence of MINECO regarding emerging PV and we are starting to be more active in AMPEA. We are currently writing other proposals (ITN and Network of Excellence) in the topic of thermoelectricity.

Finally, in terms of dissemination, our researchers have been very active, participating in Summer Schools (e.g. on Sodium Batteries in Sweden), with talks and workshops in Expominer, “Bojos per la Física” jointly organised with IFAE and ICN2, the ICMAB´s kids day, as well as in several programs (Escolab) for high school students in which we taught them to build dye sensitized solar cells and batteries.

The RL2 is devoted to creating high quality high-current superconducting tapes to enhance the efficiency and reduce the environmental impact in electricity transport, distribution, generation and use. Our superconducting long length tapes are achieved through low cost manufacturing processes, while keeping high functional performances suitable for industrial applications.

Superconducting films are grown by low cost chemical deposition methods, and we are currently developing novel growth methods with inkjet deposition. Nanocomposites with interesting electronic properties are created by nanostructuring the films. The manufacturing processes are totally scalable. The materials are characterized with advanced characterization techniques, such as electronic nanoscopy, density functional theory analysis of defects, X-ray magnetic circular dichroism and in-situ X-ray diffraction synchrotron studies, in-situ resistivity and high magnetic field transport measurements.

The superconducting materials applications belong to the power sector, especially in fault current limiters, wind generators, ultrahigh magnets, beam screens for accelerators and electronic memory devices. One of the main goals of the RL2, whose activities are internationally recognized and competitive, as clearly evidenced by many EU grants, plenary and invited talks at international meetings, ERC grants and the CERN-funded beam screen R&D for the Future Circular Collider project, is to achieve high-performance ratios and to reduce the final cost at least a factor of 5 compared to present status. Both requirements are critical to enter the market.

Students and postdocs, as well as staff members, are present at all major meetings, making the work visible, impactful and well appreciated, and to enhance the contact with the European chemical solution processing industry and work with them to devise ways to overcome the barriers to thicker film growth (3-5 µm) while still maintaining high texture and strong vortex pinning.

The RL3 is devoted to the study of transition metal oxides, which are considered to be the building blocks for efficient, and energy friendly data storage, advanced computing and energy harvesting devices. We are enthusiastically committed to and contributing in exploiting orbital physics and interface engineering to induce emerging properties, using oxides for data storage, communications and light harvesting, engineering magnetic properties, searching and understanding multiferroic materials, integrating ferroelectric and ferromagnetic oxides on silicon, tailoring electronic properties with nitrides, designing and making artificial polar materials.

We currently focus predominantly on the development of thin films of these materials with subnanometric precision, and use the most advanced tools of lithography for device microfabrication, prior to electrical, magnetic and optical characterization. Structural, morphological and microstructural analysis are done by a combination of in-house techniques (e.g. PLD) and extensive use of large scale facilities (ALBA synchrotron radiation, neutron beams, most advances electron microscopes, etc.). Theory and modeling including flexoelectrics are backed up by a recent ERC consolidator grant.

In 2017, the Scientific Advisory Board evaluated the RL3. Here we summarize the 2017 main highlights and activities.

2017 MAIN HIGHLIGHTS:

Materials Preparation:

• Integration of ferroelectric oxides on technological platforms and tuning of Polarization of BaTiO₃ by growth conditions rather than conventional substrate-induced strain control, suggesting an important role of point defects as a new knob to functionalize oxides.
• New phase discovered in multiferroic e-Fe₂O₃. This oxide was first demonstrated to be multiferroic at ICMAB and now a new magnetic phase of it has been discovered.
• Nitride tuning of magnetic, optic and electric properties of transition metal perovskites. Oxynitrides may display radically different properties than their oxide counterparts. Hole doping has been achieved in LaCrO_3-xN_x and Sr₂FeWO₅N that allows tuning magnetic properties and, interestingly enough, the cationic order in the double perovskite is preserved during the topochemical nitridation.
• Correlated cobalt oxides with spin-state and electronic instabilities. The spin-state instabilities in Co(III)-based oxides were examined in relation to their conductivity, magnetic and structural transitions.

Advanced characterization:

• Mapping Polar displacements mapped by HREM. The presence of polar displacements in otherwise non-polar LaAlO₃ films grown on SrTiO₃, has been observed and, based on first principle calculations, it has been shown that it results from a competition between distinct octahedral rotation patterns in the oxide in confined structures, in presence of a interface-related electric field.
• A new scanning probe microscopy mode to study the piezoelectric response based on the direct piezoelectric effect (dielectric polarization under an applied mechanical stress). In contrast to the widely used electromechanical characterization based in the inverse piezoelectric effect (mechanical deformation under an applied electric field), the new Direct Piezoelectric Force Microscopy allows a quantitative determination of the piezoelectric coefficients.
• Magnetic symmetry and coupled internal orders in magnetoelectric and functional oxides. Full symmetry analysis and description of internal orders and coupled modulations (crystal&magnetic ordering, charge and orbital ordering, spin-state ordering) in oxides with (i) metal-insulator transitions (ii) magnetoelectric properties and (iii) multiferroicity. Influence of distortion on the magnetic order and the magnetoelectric properties of frustrated R₂CoMnO₆ (R=Y, Ho, Tm, Yb and Lu) B-ordered perovskites. Magnetic crystallography of cycloidal multiferroics : discovery of different types of cycloidal flops and polarization rotations under magnetic field in cycloidal ferroelèctrics.
• Magnetic anisotropy and valence states in La₂Co_1−xMn_1+xO₆ thin films studied by x-ray absorption spectroscopy techniques.
• The structure of catalysis-active TiO2 based surfaces. Using synchrotron surface diffraction the structure of the rutile TiO2 (110) interface with water and that of the TiO2 anatase (101) surface have been determined.

Devices and Functionalities:

• Magnetodynamics driven by voltage-controlled surface acoustic waves (SAW). SAWs on piezo materials have been mapped using stroboscopic synchrotron light and a photoemission microscope (PEEM). Simultaneous mapping of XMCD of micrometric objects grown on the piezo substrate has allowed to obtain dynamic views of elastic waves and magnetic anisotropy at unprecedented picosecond time scale.
• Electric & mechanical switching of polarization. Epitaxial BaTiO_3-δ/La₀.₇Sr_0.3MnO₃ bilayers have been grown on Si with a columnar microstructure. This particular microstructure enables the flexoelectric switching of the BTO polarization and voltage controlled resistive switching, which can be also manipulated by a strain gradient. The combined electrical and mechanical control allows setting the system into three different configurations of polarization and resistive states.
• Electric-field manipulation of magnetic states in antiferromagnetic systems, for the magnetic memories. It has been discovered that some martensic alloys displaying ferromagnetic/antiferromagnetic transitions, f.i. FeRh, can be used to hide magnetic information and its response can be modulated by voltage-controlled strains.

Fundamental understanding and modelling of oxide physics:

• Flexoelectricity and gradient-related properties. Gradient-mediated couplings are materials functionalities that emerge from spatial variations of some order parameter (strain, polarization, magnetization, antiferrodistortive tilts), rather than the periodic bulk phase itself. Gradients generally break inversion symmetry, and thereby produce an electrical polarization (P) even in materials that are nonpolar, hence their practical interest for applications. Our group is currently leading the way in this research thrust
• Polar domain walls. Ferroelastic twin walls have received considerable attention in the past few years, as they are characterized by a net dipole moment even if the parent material is nonpolar. We have reported two new mechanisms that contribute to P: a direct “rotopolar” coupling to the gradients of the antiferrodistortive oxygen tilts, and a trilinear coupling that is mediated by the antiferroelectric displacement of the Ti atoms. These results open new avenues towards engineering pyroelectricity or piezoelectricity in nominally nonpolar ferroic materials.

2017 ACTIVITIES:

The scientific activity of RL3 has been made possible by gaining competitive financial resources from ERC (1), Spanish MINECO (5), IF-MSCA fellowship (1) and Severo Ochoa Excellence center –related FIP projects (3). This activity has resulted in a number of scientific papers published in top-ranked journals in the field. A non-exhaustive list includes: Nature Materials (2), Nature Comms (2), Adv. Funct. Mater. (1), Chem. Mater (1), Small (1). Phys. Rev. Lett. 82), ACS Applied Surface and Interfaces (1), Phys. Rev. Appl. (1), J. Phys. Chem. C (1); Sci. Reports (1), Phys. Chem. Chem. Phys. (1), Prog. Solid State Chem (1), etc, and a contributed chapter in a book.

The activities have been disseminated in major scientific forums by delivering Plenary (2), and Invited (13) lectures, in addition to about 30 oral presentations and specialized conferences and seminars at Laboratories and Universities. RL3 scientists have been chairing Conferences and Symposia (4) and been acting as Scientific Committee Members of several others. The international scientific visibility of RL3 has contributed to recruit a substantial number of Post Docs (4) and Pre-docs (9) including the prestigious InPhiNIT –La Caixa-Ochoa grant. This education activity has resulted in several PhDs defenses (3) and we have hosted Master and Graduates students for their projects and laboratory training (5). We are proud that one of the RL 3 members (Ignasi Fina) has been awarded by the “2017 Young Research Prize for Excellent trajectory” from the RSEF.

The use of organic molecules in electronic devices is arousing enormous interest due to their unique advantages for designing tailored functional materials, compatibility with low-cost production processes, biocompatibility and biodegradability. In the RL4 we focus on the fabrication of organic semiconductors and their applications in molecular electronics, to create devices that can have a strong impact on the wellbeing of society, regarding technological advances and health.

Some of the pursued devices are novel molecular switches, memory electronic and spintronic devices, low-cost organic field-effect transistors and (bio) chemical and temperature sensor devices. The devices are developed considering a holistic perspective including: design and synthesis of the molecules, structural, morphological and electronic characterization, device fabrication and integration, and theory prediction and rationalization.

Thus, the activities encompass from fundamental studies such as molecule/surface interactions or structure/property correlations to the proof-of-concept devices. The active molecular components employed are mainly based on single molecules integrated in a junction, selfassembled monolayers of the functional building blocks on a solid support and single crystal or large area coverage crystalline thin films.

In particular, the group has identified the distinctively higher conductance of radicals, in some cases also characterized as Kondo, as compared to “dead” molecular connectors. Molecular switches and other interesting effects have also been demonstrated, as well as electrochemically switchable systems based on liquid and solid electrolytes and metallocarboranes for screening of gene mutations. The line is active and proactive in their discovery and promotion, through tools including STM, AFM, Kelvin probe, etc., of nanoscale behavior, structure and geometry, and electronic behavior of deposited molecular systems, also including organic devices and engineered surfaces. 

The research activities have attracted a very high level of funding, both from national and international grants, including one ERC Starting grant, one ERC Consolidator grant and one ERC Proof-of-concept grant, international collaborations, attendance to international meetings and publications in top journals.

The strategic goal of the RL5 is to provide key inputs in two of the current challenges of nanomedicine with strong impact on societal wellbeing, especially in health: therapy, diagnosis and tissue repair. The line synthesizes nano-objects for therapy and diagnosis obtained by new manufacturing schemes and able to cross biological barriers, such as smart multifunctional drug delivery systems decorated with targeting vectors and stealth agents (nanovesicles, nanocapsules, nanoparticles, dendrimers, nanotubes, containing bioactive molecules…), and for multimodal diagnosis enabling to obtain images of the different tissues and metabolites distribution based on contrast agents magnetic nanoparticles and organic free radicals, X-ray absorbers or radionuclei.

Nanostructured materials for tissue repair to understand and control signals directing cell behavior towards vascular or neural reparation therapies are also researched. These include novel biocompatible nanostructured electrodes based on graphene with high capacity and low faradaic effects for repairing the neural system; endothelial cells and magnetic nanoparticles for cell therapy in brain neurorepair; and surfaces that trigger the organization of growth factors in a biomimetic way using electroactive molecular self-assembled monolayers for cell guidance towards vascular morphogenesis.

The actions to develop these targets are also supported by the experience on theory and simulation of soft and biomaterials. The research activities have attracted a high level of funding, an ERC Consolidator grant, and a strong interaction with industrial partners. The spin off company Nanomol Technologies has risen. The supercritical fluid processing platform is integrated in the frame of NANBIOSIS, a Spanish Scientific and Technical Singular Infrastructure (ICTS), which can be accessed both internally and externally. An in vitro cell culture work will soon be open together with the nearby ICN2 to promote this line to an even higher level.