SUMMARY
The Instituto de Ciencia Molecular (ICMol) of the Universidad de Valencia (UVEG) was founded in 2000 to develop a competitive and high-quality research in materials science using a molecular approach. ICMol is in fact the sole Spanish research center exclusively focused on the study of molecules and functional molecular materials exhibiting magnetic, electrical or optical properties. Due to these features, it has received the Accreditation as a Unit of Excellence “María de Maeztu” (2016-2019), awarded by the Spanish Ministry of Economy and Competitivity within the National Programme for Fostering Excellence in Scientific and Technical Research.
OBJECTIVES AND STRATEGIC RESEARCH LINES
The main goal of the Maria de Maeztu Excellence Unit is to deliver world-leading scientific and technological contributions to different fields of interest in molecular nanoscience using a chemical approach. Four lines of research, in which ICMol has a solid background and a strong international reputation, have been chosen:

1. Metal-Organic Frameworks
1.1 Chemically-responsive MOFs – Leader: G. Mínguez Espallargas
1.2. Highly-stable MOFs – Leaders: C. Martí-Gastaldo and E. Pardo
2. 2D Materials – Leaders: A. Forment and E. Coronado
3. Molecular Spintronics – Leader: E. Coronado
4. Molecular Electronic Devices – Leader: H. Bolink

Based on our extensive experience in the design of multifunctional molecular materials, we will explore in this Programme the design of novel hybrid materials using as chemical tools those provided by coordination chemistry and solid-state chemistry. On one hand, we will benefit of the structural versatility of coordination chemistry to engineer new magnetic metal-organic frameworks (MOFs) able to respond to an external stimulus (switching the magnetic properties upon uptake of molecules in the pores), or to design very robust MOFs which can be suitable for photocatalysis and proton transport.

On the other hand, we will focus on layered materials capable to be exfoliated as monolayers (layered hydroxides, metal dichacogenides, 2D coordination polymers,…). These graphenoid materials constitute a hot focus of interest in materials science. We will explore the molecular functionalization and assembly of these magnetic or (super)conducting monolayers to produce new hybrid materials and heterostructures of direct application in highly topical fields like energy conversion and storage, sensing or spintronics.

As the era of silicon-based technology is declining, there is a need to define new ingredients for the next generation of devices. Molecules are entering in the game due to their unique properties (ease of design, tuning, processability and addressing). Starting from its international leadership in molecular magnetism and molecular electronics, ICMol plans to be a pioneering institute in the emerging field of Molecular Spintronics, and will focus on: i) the fabrication of new spintronic devices (molecular spin valves and spin-OLEDs); ii) the interface engineering using multifunctional materials; iii) the design of single-molecule spintronic devices; iv) the search for robust spin-qubits based on single-molecule magnets.

ICMol is one of the leading European institutions in the field of Molecular Electronic Devices, investigating the development of solution processable, electroluminescent and photovoltaic devices employing air-stable electrodes. Main objectives in this line are the development of i) thin film light emitting devices with efficiency of 100 lm/W; and ii) thin film organic-inorganic perovskite solar cells with 20 % efficiency. These devices are very much in the spotlight since they increase the efficiency of energy consumption and generate clean energy, respectively. This line involves a close collaboration between experimentalists and theoreticians.

LINE 1: METAL-ORGANIC FRAMEWORKS

1.1. Chemically-responsive MOFs. Leader: G. Mínguez Espallargas
We will develop functional MOFs capable of interacting with guest species. The chemical stress originated by the guest will be aimed to modify the physical properties of the framework, thus acting the framework as a sensor. Different functionalities in the framework will include luminescence, thermochromism and, in particular, magnetism. ICMol has a wide expertise in the design of multifunctional magnetic materials using a molecular approach. The new class of stimuli-responsive materials we propose to develop in the next four years represent a second generation of multifunctional molecular materials in which a fine-tuning of the structure of the functional coordination network will enable to control the absorption of molecular species and, therefore, its properties.

1.2. Highly stable MOFs. Leaders: C. Martí Gastaldo and E. Pardo
Highly stable MOFs will be based on unexplored functional groups and metal-oxo clusters that overcome current hydrolytic limitations of MOFs imposed by classical linkers and enable accessing advanced crystalline materials with enhanced hydrolytic stability and tunable performance. Poor hydrolytical stability is the key drawback of MOF chemistry nowadays and is severely limiting their use as functional porous materials in applications of broad interest like heterogeneous catalysis. Overcoming this limitation would position ICMol at the frontier of synthetic knowledge in MOF chemistry and would have an enormous impact in Chemistry and Materials Science. We also aim to prove the value of our approach by evaluating the performance of these solids in two topical applications: heterogeneous photocatalysis and proton transport. Here the newly gained chemical stability will be combined with other intrinsic features of MOFs, like isoreticular chemistry and chemical versatility, for optimizing their electronic properties or transport of charge carriers.

LINE 2: TWO-DIMENSIONAL MATERIALS. Leaders: A. Forment and E. Coronado
The study of graphene and other 2D crystals is a hot focus of research in materials science. So far, this field has been dominated by conductors (graphene) and semiconductors (MoS2, for example). In the next four years we will contribute to this field by studying other classes of 2D materials. We propose in particular to put superconductivity and magnetism in the game through the study of superconducting 2D materials based on metal dichalcogenides (TaS2, for example), and of magnetic 2D materials based on layered coordination compounds. With respect to the 2D superconductors we will use the experience of ICMol in the growth of crystals and in their exfoliation using both micromechanical and solution techniques. With respect to the 2D magnets, we will take advantage of our unique expertise in coordination chemistry and molecular magnetism to prepare these layered magnets. We propose to isolate and grow atomically-thin layers of these compounds, to study their properties in the 2D limit, to functionalize them with the appropriate molecules, and to assemble them to create hybrid materials showing multifunctional or stimuli-responsive properties.

LINE 3: MOLECULAR SPINTRONICS. Leader: E. Coronado
This new area combines the ideas and concepts developed in spintronics -the most active area within nanomagnetism- with those coming from molecular magnetism and molecular electronics. The ultimate goals in this research front are to exploit the unique possibilities offered by the molecular systems to create new spintronic devices using molecule-based materials or, in the longer term, one or a few molecules in the race toward miniaturization.

3.1. Molecular analogs to the inorganic spintronic devices.
Some specific goals are to design molecular spintronic devices with improved spin transfer and transport properties; to incorporate molecules at the interface between the inorganic spin injector and the organic spin transporting layer with the aim of tailoring the spin transfer at the hybrid interface; to develop new smart interfaces based on multifunctional molecular materials, in particular multiferroics, and stimuli-responsive magnetic materials; to fabricate multifunctional spin-OLED devices.

3.2. Evolution towards single-molecule spintronics.
In the short term it involves the study of the conductivity through single magnetic molecules, in particular the study of the interplay between transport properties and nanomagnetism. A major aim is to control the molecular spin by applying an electric field. In the long term it involves the use of these individual magnetic molecules (molecular nanomagnets, in particular) as active components of nanospintronic devices (including ultra-high density information-storage devices and applications in quantum computing). In this last topic the major challenge will be that of minimizing the sources of quantum decoherence in molecular spin-qubits in order to obtain robust spin-qubits. Our approach in this context will consist of using lanthanide single-ion magnets based on nuclear spin-free polyoxometalates as starting molecules.

These challenging goals represent a radically new scientific endeavour in molecular magnetism, which needs to evolve from the chemical synthesis of bulk molecule-based magnets to the design, study and manipulation of single-molecules and magnetic nanostructures using the concepts and techniques developed in molecular nanoscience.

LINE 4: MOLECULAR ELECTRONIC DEVICES. Leader: H. Bolink
Molecular electroluminescent devices are planar large area light sources that are used on an industrial scale for the preparation of displays and are emerging as alternative luminairs. Especially for lighting, the currently used OLEDs prepared by subliming multi-layered structures have a prohibitive cost structure. Thus, large gains in reduction of electricity consumption can be obtained if such devices can be made more economically. ICMol is coordinating a H2020 project (SOLEDLIGHT) with participation of the companies Osram and Solvay that aims to prepare highly efficient OLEDs using solution processing.

Perovskite based photovoltaic devices emerged 4 years ago and efficiencies of 20 % have already been reached. These devices are very similar in structure and employ similar processing steps as the ones used in organic photovoltaics, yet the efficiency is double and the cost of the starting materials is a fraction. Hence, these devices have the potential to compete favourably with silicon and increase their efficiency in tandem structures. As already pointed out, ICMol is among the pioneers in the field, in particular in the thin film processing method to prepare perovskite layers and their integration in the simplest thin film devices. Apart from the project “FAFOR” with Abengoa (funded by MINECO), we are awaiting the evaluation results of three H2020 projects related with this topic, one of which submitted to the Low Carbon Energy call in which ICMol is coordinator and has passed the first stage evaluation.
RESEARCH GROUPS
- Research Unit on Molecular Materials:
Group of Molecular Nanomagnetism and Multifunctional Molecular Materials (E. Coronado)
Group of Theoretical Molecular Magnetism (J. M. Clemente-Juan)
Group of Molecular Opoelectronic Electronic Devices (H. J. Bolink)
- Research Unit on Coordination Chemistry:
Group of Magnetic Molecular Materials based on Coordination Chemistry (M. Julve / F. Lloret)
Group of Switchable Molecular Materials (J. A. Real)
- Electroactive Molecular Materials group (E. Ortí)
- Supramolecular Chemistry group (E. García-España)
- (Photo)Chemistry Reactivity group (J. Pérez-Prieto)