Mapping energy carriers

How can we map out traps on a surface? Ferry Prins, Michael Seitz et al. have developed a curious strategy. First, they’ve injected a small population of excitons (gaussian shaped) in a 2D metal halide perovskite. The flow of these excitons through the material will be affected by the traps, kind of how the flow of water is affected by stones at the riverbed. Therefore, by visualising the flow of the excitons, you can “accurately map out the trap-state landscape in the perovskite lattice”.

This research, has been featured in the cover of Advanced Optical Materials. The picture has been done under the supervision of Ferry Prins and Michael Seitz.

Van der Waals on paper

We’ve been talking for quite a long time about the crazy things that happen in Andres Castellanos’s Lab. And they seem to be getting crazier. The ability of this people for outside the box thinking is amazing. Actually they don’t seem to know about the box at all!

They are now working in the use of paper as a functional substrate for van der Waals materials. This materials are deposited by “simply rubbing the vdW crystals against the rough surface of paper”. The aim is to replace silicon with a cheap material. But is it paper a valid substrate? In this new work, they’ve characterized the optical and electronic properties of some of this materials in this strange new conditions. As vdW materials can behave as superconductors, insulators, semiconductors or semi-metals, researchers have to prove all these properties are maintained when transferred into paper.

And that is exactly what they did by building field-effect devices using the paper substrate as an ionic gate. This work, published in Applied Materials Today, has been featured in the cover.

Hot carriers thermalization

A research collaboration between IMDEA Nanociencia, DIPC and IFIMAC led by Roberto Otero has just proposed a new method to measure electronic temperatures in metallic nanostructures.

In particular, they show that the electronic temperature can be derived from “the shape of the tunnel electroluminescence emission edge in tunnel plasmonic nanocavities”.

This method, published in Nanoletters, will allow the study and understanding of the thermalization of nanoscale systems with picosecond resolution.

Osmium is the key

Ana Pizarro and colleagues are a sort of modern watchmakers to my eyes. But instead of using gears and springs, they work with atoms, bonds and molecules. They carefully tailor them to produce chemical reactions in specific places that are triggered by specific conditions. In particular, they’re putting a lot of effort in molecules that work as catalysts in the cytoplasm and are triggered by pH changes.

This time they bring to our attention this beautiful specimen: [Os(η61-C6H5(CH2)3OH/O)(XY)]+ an osmium(II) tethered half-sandwich complex that has shown to carry out transfer hydrogenation reactions inside cells in a reversible way. The particular properties of this molecule could give it a central role in cancer therapies.

This work, published in Chemical Science has been featured in the cover with this image we did together with Ana Pizarro.

Towards healthier photovoltaics.

Science is always teaching us how to do new things. But it is also important how it teach us how to do old stuff in a much better way. And with better we mean, in a faster, cleaner, healthier, more sustainable way. And that is kind of what Vincenzo Pecunia et al. do in their last paper.

They’ve developed a technique to study the impact of defects in lead-free-perovskites inspired materials. These materials are gathering a lot of interest since they can be key to the development of green, high-performance photovoltaics. And the efficiency of these materials is closely related to their defect tolerance.

This new technique is not only highly sensitive but it is also facile and widely applicable. We did this picture together with Vincenzo Pecunia and it has been featured in the cover of Advanced Energy Materials.



Smart AFMs

Machine learning is already a thing and it is slowly percolating into the most unexpected places. AFM is its most recent victim and Juan F. Gonzalez-Martinez et al. (Biofilms-Research Center for Biointerfaces at Malmö Univerity) have put them together.

Although deep learning techniques had already been used for AFM related analysis, for the first time (to my knowledge) it’s been used to drive the microscope to locate particularities of the samples. They have used Plasmid DNA from E. coli with assubject, and the challenge was to teach the microscope to identify and distinguish single molecules and take images of them with different lateral resolutions.

Although this type of studies is not technically challenging, doing them is extremely time consuming because it needs the close supervision of the researcher. Thus, this breakthrough could open the door not only to a full autonomous AFM but to the analisys of large amounts of samples and statistically significant studies.

We did this picture (featured in the inside cover of Nanoscale) together with Javier Sotres, first author of the paper.


Superconductors work (on paper)

Castellano’s Lab (ICMM-CSIC) research is not only top-notch scientific work: more important, at least to me, it is funny and inspiring. They’ve also worry about the social, economic and environmental impact of technology. And we can see all that in their last paper.

Together with the Kavli Institute of Nanoscience (TuDelft) they’ve proved that it is possible to have a working van der Waals superconductor deposited on regular paper as opposed to crystalline silicon. In particular, they’ve reported the observation of  Meissner effect and resistance drop to zero-resistance state at low temperatures. As they point out, regular paper is 10.000 times cheaper that crystalline silicon. And being this technique scalable, it could have a major effect on the production of magnetic field shielding or superconducting high frequency filters.

We collaborated with them in the production of this picture that has been featured in the cover of Materials Advances.

Superconducting graphene

Graphene’s business card is running out of space. We’ve already seen it doing nearly every possible thing in condensed matter physics. And superconductivity was to be there. It was a matter of time.

Magnetism and superconductivity don’t get along… to put it politely. So when you add magnetic atoms into a superconductor, the superconducting order is locally broken and spectral features (called Yu-Shiba-Rusinov states) appear inside the superconducting gap. And this features are important because they might be useful for quantum computing. 

Ivan Bruhuega, has lead an important research collaboration involving several countries (Finland, France, Portugal and Spain), that has for the first time observed these Yu-Shiba-Rusinov states in graphene. The complexity of this experiment is hard to grasp. To begin with, you have to induce superconductivity in graphene. They’ve done this by growing nanometer scale superconducting Pb islands over it. And then, using scanning tunneling microscopy and spectroscopy they’ve visualized Yu-Shiba-Rusinov states in the graphene grain boundaries. Quite a challenge.

We made this picture to illustrate the experience and it’s been featured in the cover of Advanced Materials.

Anti-metastatic treatment for breast cancer

Nanosized drug delivery systems based strategies are slowly changing our view of medical treatment. They can be applied to a wide variety of diseases and Dr. María J. Vicent (Polymer Therapeutics Lab) and Dr. Marcelo Calderón (POLYMAT) are designing new approaches expand their usage and improve their efficiency.


In their last work, they deal with triple negative breast cancer and its associated metastasis, for which we lack effective treatments. In their recent paper in Journal of Controlled Release, they propose “injectable poly-amino acid-based nanogels as a versatile hydrophilic drug delivery platform for the treatment of triple negative breast cancer lung metastasis”. These nanogels deliver the chemotherapeutic agents in more restricted, specific areas increasing their efficiency thus reducing their aggressiveness.

We designed this representation of the drug delivery process under the supervision of  María J. Vicent and Marcelo Calderón. Their work has been featured at the cover of JCR.

On pandemics, flexible spikes and mechanical stability

The SARS-CoV-2 is covered by a layer of “spikes” whose mobility (yet to be determined) has been proposed to be related to the infection process. Miklós S. Z. Kellermayer et al. (Semmelweis University, Budapest) “by imaging and mechanically manipulating individual, native SARS-CoV-2 virions with AFM” have proved that this layer is in fact dynamic. The virions show also a remarkable resistance to deformation and they’re able to recover from extreme mechanical deformations. You can read the details in their paper published in Nanoletters.

As a side note, the AFM experimental images they’ve published are just beautiful.

To illustrate the experiments we made this picture, under the close supervision of first author, Bálint Kiss, which has been featured in the cover of Nanoletters.