A strain tunable single-layer MoS2 photodetector

Lets take a single layer of MoS2. Lets attach it to a surface in such a way that it can be stretched (or compressed) and there you have it: A strain tunable single-layer MoS2 photodetector. A device which uses strain to change the electrical and optical properties of 2D materials. In particular they’ve proven that with this method, they can reversibly change the photoresponsivity, the response time and the spectral bandwidth of single layered MoS2.

At Dr. Castellanos Lab, they are excelling at beautiful and elegant research. “… we demonstrated that applying tensile biaxial strain to the MoS2 device can be an effective strategy to increase both the responsivity and the wavelength bandwidth of the photodetector (at the expense of a slower response time), while compressive strain can be exploited to yield faster photodetectors (although with a lower photoresponse and with a narrower wavelength bandwidth). This adaptable optoelectronic performance of this device can be very useful to adjust the photodetector operation to different lighting conditions, similarly to human eye adaptability (scotopic vision during the night vs. photopic vision during the daylight).

Their research is a collaboration between ICMM-CSIC, Imdea Nanociencia and the State Key Laboratory of Tribology, Tsinghua University, Beijing and has been recognized with the inner cover of Materials Today.

It comes in colors everywhere

A research group at IMDEA Nanociencia (together with the University of Grenoble and Berkeley) have presented a new switchable iron-based coordination polymer, which works as a reversible acetonitrile sensor.

Coordination polymers are emerging as molecular sensing materials for a variety of reasons: they are not toxic, environmentally friendly and above all, they’re highly responsive to a wide variety of external stimuli.

This polymer in particular, the unutterable {[Fe(H2O)2(CH3CN)2(pyrazine)](BF4)2·(CH3CN)2}, happens to be an excellent acetonitrile sensor: a toxic volatile organic compound, that makes its detection a major issue. The desorption of interstitial acetonitrile changes reversibly the color of the polymer together with its electronic and magneto–structural properties.

On request of José Sánchez Costa and Enrique Burzuri we made this picture, showing the reversibility of the process, that made it to the back cover of Chemical Science.


Waves and Stress

Measuring the mechanical strength of a material at the nanoscale is challenging . If the object we are measuring happens to be a two-dimensional material, the task amazingly difficult. But people at Castellanos-Gómez Lab are really smart. They’ve adapted a method (already used with organic thin films) to determine these materials Young Modulus that, apart from other advantages, does not require the material to be freely suspended.

To make a long story short, they compress the material. Not been freely suspended, ripples appear all over the material. The wavelength of this ripples depends only in the elastic properties of the film and the substrate, so voilá! Frankly, much easier to explain than to perform.

These results were published in Advanced Materials.

To illustrate it, and requested by Dr. Andrés Castellanos-Gómez, we did this image that made it to the back cover of Advanced Materials.

Demoreel 2017-2018

This demo has taken two years… documentaries, advertising, covers, pictures… we’ve been pretty busy lately.

Nucleation of pseudo hard-spheres

I would love to be intelligent enough to say something smart about the research of Eva González Noya, but I can’t. I know it has to do with the simulation of nucleation processes… and that’s all I have.

What I know instead is that she always gets the cover. And this time was not different.

Bioinformática con Ñ

5 years ago now, several Spanish researchers, got together to write a book describing the principles of bioinformatics. Alberto Pascual-García and Álvaro Sebastián asked us to give a hand in this free, collaborative project by designing the cover of the book. And this is what we did, in the early days of Scixel.

Keeping it clean!

Several modern applications require antireflective transparent materials. We try to avoid reflections in our screens and clean transparent coatings are essential in solar panels. Scientists have been looking for a clean, cheap and durable solution for quite long. And this is exactly what Prof. Isabel Rodriguez et al. have recently reported in Nanoscale.
Thanks to this collaboration (IMDEA Nanociencia & IMDEA Materiales) a new coating system has been developed. The methodology involves the fabrication of sub-wavelength moth-eye nanofeatures onto transparent surface composite films in a combined processing step of nanoparticle coating and surface nanoimprinting.

With this approach they’ve been able to reduced the optical reflection losses from values of 9% of typical PMMA plastic films to an optimum value of 0.6%.

We made this picture (which appeared in the back cover of Nanoscale) with the supervision of Prof. Rodriguez. It represent both the high transmission coefficient of this new coating system and its durability.

The perfect blend

FRET is a mechanism describing energy transfer between two light-sensitive molecules. Dr. Juan Cabanillas (IMDEA Nanociencia) et al. have studied different fluorene-based polymer blends to produce low threshold lasers operating between 540 and 590 nm (green/yellow). They’ve established the optimal conjugation length of the polymers (number of units) which produces a 4 times increase in optical gain and a 34 reduction in amplified spontaneous emission threshold.

In this paper it is proven how a careful configuration dramatically improves the efficiency of these systems, suggesting a lot of space for improvement. These materials show to be of great interest for electrically pumped light emission struc­tures including LEDs and LETs.

This research has appeared in the cover of Advanced Functional Materials.

The scouts finally arrived

A few months ago we made a press release on the recent work of Prof. Pere Cusachs: a beautiful research where they study how the cell interacts with its environment.

We help them made a beautiful image for them, picturing a cell exploring its surroundings. That image got particularly popular, making it to PhD manuscript covers and even t-shirts.

Finally, a different version of the picture made it to the cover of a biology journal: Trends in Cell Biology