In organic photovoltaics (PV), the high-throughput experimental screening and characterization approach based on lateral parametric gradients (measuring-intensive) developed at ICMAB has been combined with machine-learning algorithms to retrieve quantitative structure–activity relationships and extract molecular design rationale, accelerating organic solar-cell material discovery. Regarding complex oxides for PV applications like of BiFeO3, its phase stability and optoelectronic performance was enhanced and a cost-effective route to prepare freestanding complex oxide films was developed. Concerning hybrid lead halide perovskites, the first systematic assignment of common features apparent in the low-temperature PL spectra of single crystals to shallow defects was performed.
A combined strategy based on light trapping in 2D photonic crystals and plasmonic resonances has been successfully implemented for hydrogen production by photo-catalysis in the visible. Furthermore, it has been shown that redox gradients generated by wireless electrochemical processes, for example, in electro-deposited iridium oxide strongly enhance O2 evolution kinetics with applications in electro-catalysis and neural growth.
Regarding thermal transport, the recent experimental observation of “second sound” in bulk Ge even at room temperature and its modeling and simulation using nonequilibrium molecular dynamics open a new research field of wave-like heat transport, potentially, in almost any material. Further advances in general theory involve the development of workflow interfaces that automatically compute material properties and the derivation of a dielectric-screening theory in quasi-2D materials.
Batteries based on multivalent ions (e.g. Ca2+, Mg2+) and metal anodes could enable very high energy densities, thus, activities within 2021 included the screening of new materials as potential cathodes for Ca metal batteries using operando techniques and the development of boron-containing electrolyte additives. Carbons derived from alcohol-treated bacterial cellulose with optimal porosity were obtained, showing excellent behavior for Li-O2 Batteries.
New hybrid nanocarbon-metal oxide electrodes were developed for supercapacitors using innovative laser-based electrode fabrication methods, which were further up-scaled to meet industrial standards.
Highly flexible 3D porous metal–organic frameworks (MOFs) were modified to incorporate conducting polypyrrole, so as to enhance their stability and capacitance as electrode material. Nanocomposite aerogels made of MOFs and graphene oxide have been developed for efficient CO2 and CH4 adsorption and separation.
This Research Line is devoted to deploy unique know-how in superconducting materials and their use in emerging areas of energy, efficient ICT, high energy physics and astrophysics. In particular, our effort was concentrated in three main aspects. Firstly, in developing high-throughput, low-cost growth methods for Coated Conductors (CC) with engineered properties to approach theoretical limits. Also, in investigating superconducting electronic functionalities based on controlling properties of cuprates for ICT and impelling ultrasensitive Transition Edge Sensors (TES) as single photon and phonon detectors. Finally, in customizing CC materials for adequate integration in large scale systems (energy and high energy physics).
We recognize the breakthrough in Transient Liquid Assisted growth (TLAG) of cuprates where 1000 nm/s growth rates were demonstrated by in-situ XRD synchrotron investigations. This fostered to design and building of a stable installation at ALBA synchrotron within the TransEner PTI+. In addition, this research has attracted industrial interest, and during 2021, a project was signed with Sumitomo Electric Inds and an ERC-PoC was executed.
In the investigation of electronic functionalities, electric-field manipulation of the superconducting to insulator phase transition and electromigration effects were explored in cuprates, and the potentiality of hybrid systems for efficiently manipulating non-trivial spin textures and guide magnetic fields was demonstrated.
Besides, in 2021 we worked on electrothermal modelling of TES and devised the analysis of transition mechanisms for their better understanding and optimization. Notably, we started a project to develop TESs for low-mass dark matter direct detection.
Our scouting activities in customization of CC has led to define a robust architecture to increase the quench velocity and consequently enhance the electric field generated in superconducting fault current limiters (patented). Additionally, we have consolidated the understanding and development of a superconducting coating technology for high energy physics instrumentation (FCC high-energy accelerator and Axion detector cavities) with the complementary understanding of CC high frequencies response at magnetic fields.
The research line has progressed in the understanding of the ferroelectric phase of epitaxial HfO2 thin films, a key material in the spotlight of the memories industry. Researchers of the RL exploit this knowledge to engineer ultrathin tunnel barriers for memory applications and neuromorphic applications.
Polar materials are also investigated in the context of flexoelectricity and the interaction with light. In this regard, flexoelectric responses of two-dimensional materials has been fully calculated from first principles, of interest for applications to graphene, silicene, phosphorene, boron nitride, and transition-metal dichalcogenide monolayers. Along these lines, switching of polar metals via strain gradients have been also studied via first-principles theory. On the other hand, the photoresponse of polar oxides has been exploited to control ferroelectric memories, showing that the photocurrent can be reversed via polarization switching.
RL3 researchers have also demonstrated the role of relative humidity and polarization switching history on the surface charge dissipation in ferroelectric Pb(Zr0.2Ti0.8)O3 thin films. Other discoveries relate to the finding of a metallic monoclinic VO2 phase that bridges the metallic rutile and insulating monoclinic ground states, promoting the formation of tweed microstructures. On the other hand, indium-free metallic electrodes based on SrVO3 have led to the discovery that the effective electron-mass enhancement, responsible for its transparency at visible range, is due to electron-phonon coupling rather than electron-electron correlations, as commonly accepted.
Potential high-temperature multiferroics have been investigated based on YBaCuFeO5 multiferroics: the modulation of spiral planes and Fe/Cu cation disorder has been exhaustively determined, which is crucial to engineer and develop these materials towards high-temperature multiferroics.
Finally, spintronic activities have been reinforced by the incorporation of an ERC grantee, who has been awarded by 2021 IUPAP Young Scientist Prize in the field of Magnetism, in recognition for the outstanding contributions in the field of magnetic oxides for spintronics.
The design and synthesis of new molecules with appealing optical and magnetic properties has been pursued. Efforts have been placed in gaining new insights into the transport properties of single molecules by integrating them in molecular junctions. For instance, magnetoresistance at room temperature was found in Co(II) and Cu(II) metalloporphyrin-based supramolecular devices characterised by STM using a magnetic tip.
Additionally, the influence of the bias polarity was found to determine the transport mechanisms in self-assembled monolayers of a redox active molecule (i.e., tetrathiafulvalene) measured by EGaIn. Regarding the optical properties, monosubstituted and disubstituted carboranyl pyrazoles were used as ligand to obtain polynuclear Cu(I) compounds with interesting luminiscence properties.
Finally, work has also been placed on the development of low-cost large area devices based on printed semiconductors. In particular, recently it was reported the exploitation of electrolyte-gated organic field-effect transistors to monitor events occurring at the water/metal interface, such as the formation of a surfactant monolayer. The impact of dopants on the electrical properties of organic semiconductors have also been investigated and reviewed.
RL5 generated scientific and technological knowledge on the synthesis and processing of new materials of interest to biomedical companies and clinical groups for improved diagnosis and treatment of diseases by increasing the selectivity, efficiency and safety of the nanomedicinal system. RL5 has contributed in its three research areas:
RL5 participated defining the challenges of nanomedicine in the coming decade in line with the scientific and technological guidelines of the CSIC, contributing to the published “White Book of CSIC 2030”