Introducing our new DENSsolutions brand identity

Introducing our new DENSsolutions brand identity

Logo transition illustration
In a time where communication is evolving primarily online, the ability to adapt has never been more crucial. We recognize the importance of growth and modernization, especially within this high-tech industry, and have updated our brand identity to reflect just that. Part of this process entailed analyzing our core values as a company and how we can effectively address the needs of this dynamic world of research. This analysis resulted in the recognition of three core values that encapsulate the heart of our company: care, innovation and delivery.

We care

At the very core of all of our innovations, our technology and our solutions is that we care about your research. We want you to have the best possible equipment, be able to discover new phenomena and get unique yet reliable results that allow you to answer your scientific questions and publish in high impact journals.
This care goes beyond design and manufacture, we provide support whenever and wherever it is needed. We also aim to be the global hub for the In Situ research community, connecting you with peers all across the world.

HugoHugo with Angus Kirkland

CTO Hugo Pérez with University of Oxford Professor Angus Kirkland 

We innovate

With researchers constantly pushing the boundaries of knowledge, we make sure that our systems push the boundaries of innovation. This is at the heart of our second core value: we innovate. This way, you can rest assured that you are operating the best stimuli supply and measurement systems on the market, giving you the necessary tools to make groundbreaking discoveries. Whatever the application, from materials science to catalysis, you can ultimately create a sample environment almost identical to the real world.

DENS employee looking at a holder

Previous Mechatronics Engineer Diederik Morsink observing a holder in our offices

We deliver

We acknowledge how precious your time is and how crucial our cutting-edge technology is for your research. Through our worldwide distributor network, we strive to make sure that you receive your equipment in time. In efforts to adapt to the travel limitations of today, we have comprehensive remote installations and trainings for all of our solutions so that you can operate our systems with confidence, no matter where you are.

Magda with Climate cradle

Warehouse Supervisor Magda Wierzba handling Climate system delivery

We are delighted to be able to share our updated brand identity and the core values driving our company forward. Although our solutions are used to observe nanoscale phenomena, there is a huge amount of commitment, drive, and logistics involved behind the scenes. With our values of care, innovation and delivery at the forefront, DENSsolutions will continue to develop advanced in situ electron microscopy systems that promise reliability and accuracy every time.
Markus article feature image

New measuring technique proves exceptional temperature accuracy of our Wildfire Nanochip

In collaboration with Utrecht University, we develop a novel technique to measure temperature at the nanoscale, showing the remarkable temperature accuracy and homogeneity of our Wildfire Nanochip

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New measuring technique proves exceptional temperature accuracy of our Wildfire Nanochip

New measuring technique proves exceptional temperature accuracy of our Wildfire Nanochip

In collaboration with Utrecht University, we develop a novel technique to measure temperature at the nanoscale, showing the remarkable temperature accuracy and homogeneity of our Wildfire Nanochip

Original article by Thomas P. van Swieten, Tijn van Omme, Dave J. van den Heuvel, Sander J.W. Vonk, Ronald G. Spruit, Florian Meirer, Hugo Pérez Garza , Bert M. Weckhuysen, Andries Meijerink, Freddy T. Rabouw and Robin G. Geitenbeek
Thomas article feature image

The temperature-sensitive luminescence of nanoparticles enables their application as remote thermometers. In fact, the size of these nanothermometers makes them ideal to map temperatures with a high spatial resolution. Yet, conducting high spatial resolution mapping of temperatures that exceed 100°C poses some challenges.

In collaboration with Thomas van Swieten and his fellow colleagues at Utrecht University, we were able to jointly develop a new technique to measure temperature at the nanoscale. In fact, we tested this novel technique on our Wildfire Nanochip and were able to further confirm the Nanochip’s unparalleled temperature accuracy and homogeneity. These experiments also proved how well our models work to predict the temperature distribution across the microheater. Importantly, this particular technique will improve the accuracy of nanothermometry as a whole, not only in micro- and nano-electronics but also in other fields with photonically inhomogeneous substrates.  

The technique: Luminescence nanothermometry

Thermometry on the microscopic scale is an essential characterization tool for the development of nano- and microelectronic devices. However, conventional thermometers like thermocouples are often unable to reliably measure the temperature on this length scale due to their size. This is precisely where remote temperature sensing via optical thermometry techniques comes into play. Thermometry based on luminescence is particularly interesting since it is easily implemented, requiring only the deposition of a luminescent material in or on a sample of interest and the detection of its luminescence. For this reason, luminescence nanothermometry is currently developing into the method of choice for temperature measurements in microscopy.

Homogeneous heat distribution

Our Wildfire Nanochip was specifically designed to enable users a homogeneous heat distribution across the microheater where a sample is positioned. It is particularly due to the unique geometry of the metal spiral, where the windows are placed right at the center, that users are able to enjoy such a remarkable temperature homogeneity. In fact, our Wildfire Nanochip has a temperature uniformity of 98% across the window area and 99.5% across the two central windows. The figure on the right below is a perfect illustration of the chip’s exceptional temperature homogeneity, showing the temperature profile across the membrane and the microheater for a center temperature of 523 K simulated with a finite element model.

The high temperature homogeneity of our Wildfire Nanochips is also owed to the fact that the metal heating spiral is embedded in a silicon nitride membrane. Silicon nitride has many advantages including being chemically inert, mechanically robust and can withstand harsh chemical and temperature environments. 

Tijn article - figure 2 wildfire nanochip homogeneous distribution

On the left: The Wildfire Nanochip, where the metal spiral is represented in orange and the silicon nitride membrane in blue. On the right: Finite element model simulation showing the remarkable temperature homogeneity of the Wildfire Nanochip

Reliable temperature mapping

In this work, the luminescent particles that were used are NaYF₄ nanoparticles doped with Er³⁺ and Yb³⁺. These particles exhibit a strong upconversion when excited with an infrared laser. In other words, they emit photons with a shorter wavelength than the excitation photons. As shown in the figure below, we found that the spectrum of the emitted (green) photons is quite sensitive to temperature.

Tijn article - Figure 1 Intensity vs Wavelength

Green upconversion luminescence of the nanoparticles upon excitation at various temperatures ranging from 303 K (dark red) to 573 K (yellow)

By scanning the laser across a layer of deposited nanoparticles in the confocal microscope, we were able to capture an array of emission spectra. We then converted this emission spectra into a temperature map using the luminescence intensity ratio of the 2 peaks at each pixel. After a number of correction steps, the technique showed a remarkable precision of 1-4 K with a spatial resolution of ∼1 micrometer. It is noteworthy to mention that most other techniques are unable to achieve such a high accuracy like this.

Tijn article - Figure 3 DESKTOP reliable temperature mapping

In a) we scanned the laser across the microheater with the deposited luminescent nanoparticles to generate a map of intensity ratios. b) shows the spectrum at each pixel converted into a temperature to provide a temperature map of the microheater.

Simulation and model accuracy

Using the fully corrected temperature maps, we were able to analyze in depth the temperature homogeneity of the microheater. The figure below shows the horizontal traces through the center of these maps. The simulated temperature profiles (lines) show an excellent match with the experimental traces (dots).This confirms both the reliability of the finite element model as a design tool and the strength of our temperature mapping technique as a characterization tool, achieving a high accuracy and a spatial resolution of ∼1 μm.

Tijn article - temperature mapping in graph

A graph showing the mapping of elevated temperatures. The lines represent the simulated temperature profiles and the experimental traces represent the dots.

We determine the standard deviation of the temperature in the center to quantify the accuracy of this thermometry method and find values of 1 K at 323 K increasing to only 4 K at 513 K. Conclusively, this makes nanothermometry using confocal luminescence spectroscopy a promising method to map temperature profiles not only for microheaters but also in other fields such as biology and catalysis where temperature variations are important but hard to monitor with conventional methods.
Tijn portrait image
“Thanks to the exceptionally good spatial and temperature resolution of this method, we were able to obtain an accurate temperature map of our microheater spiral. This confirmed the excellent temperature homogeneity which was predicted by our finite element models.”
Tijn van Omme
Microsystems Engineer |  DENSsolutions

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The first in situ observation of layered metastable heterostructure formation

Using our Wildfire system, scientists are able to thoroughly investigate the formation of heterostructures from starting materials with vastly different properties

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The first in situ observation of layered metastable heterostructure formation

The first in situ observation of layered metastable heterostructure formation

Using our Wildfire system, scientists are able to thoroughly investigate the formation of heterostructures from starting materials with vastly different properties

Original article by Markus Terker, Lars Nicolai, Samuel Gaucher, Jens Herfort and Achim Trampert

Markus Terker top image in article graph

A plot showing the STEM images taken of the heterostructure demonstrating a tendency for disordered layers to order over time with annealing

Heterostructures, semiconductor structures composed of solid-state materials with different chemical properties, have found use in a variety of specialized applications where their unique characteristics are critical. The engineering of heterostructures is an important means in creating novel device concepts. In fact, it has already revolutionized the development of solar cells, transistors and even lasers. However, layering materials with vastly differing properties poses complex challenges.

Using the DENSsolutions Wildfire system, Markus Terker and his colleagues from the Paul-Drude-Institut in Berlin, Germany observe for the first time the atomic formation of a layered, metastable iron germanium crystal via two-step phase transformation. This research opens doors towards the design and formation of novel hybrid materials that combine vastly different properties, such as ferromagnets and semiconductors, and has appealing implications for optical-electronic industries.

Heterostructural interfaces and stability

Heterostructural interfaces are fundamental and versatile tools when designing electronics with varying properties, such as magnetic, optical, and transport capabilities. Since these interfaces can be used to stabilize otherwise metastable structures, understanding their structures and formation is essential to harnessing the full potential of these materials. Shedding new light on the growth of these interfaces from disordered to ordered states opens up the potential for new applications of this technology.

In this research, Terker and his colleagues observed the in situ annealing of two materials and the resulting FeGe₂ alloy interface between them. This gradual process, catalogued in the figure below, shows the crystallized FeGe₂ at the interface slowly ordering itself into layers of material.

Markus Terker figure 1 showing snap shots of annealing

In situ snapshots of the alloy interface ordering itself into periodic layers over the span of 60 minutes

From disorder to order

The starting sample consisted of a layer of Fe₃Si interfaced with amorphous germanium, a semiconductor. Heating the sample to 300 °C initiated the crystallization process and a thin layer of FeGe₂ crystal formed at the interface. This layer then grew as the sample was sustained at this temperature for the duration of an hour.

Whilst the sample was heated, in situ images were taken of the progression of the FeGe₂ crystal as it grew along the surface of the Fe₃Si base. After 15 minutes of annealing, the majority of the amorphous germanium film completely crystalized and reduced in size and disorder. However, this stage was still not completely ordered. By the 30-minute mark, the amorphous film completely crystalized and gradually ordered itself layer by layer until the entire film was in an ordered phase. 

STEM images of the (b) disordered and (c) vacancy-ordered structure of FeGe₂ observed. Atomic models of the (a) disordered and (d) ordered phase of FeGe₂ observed. The colored dots indicate the atomic stacking order.

Metastable structure

Although it was expected that pure germanium would form during this solid-phase epitaxy, the researchers observed something else entirely. A strong diffusion of iron into the germanium film was detected at relatively low crystallization temperatures. Moreover, instead of pure germanium with a diamond structure, an epitaxial film with iron content was obtained. High-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) confirmed that the resulting crystal had a different metastable crystal structure to what was expected. The figure below shows the heterostructure produced after the annealing process. 

The heterostructure produced after the annealing process

STEM images taken of (a) the heterostructure produced after the annealing process, and (b) a magnified image of the dotted black box showing the vacant layers

Novelty in findings

Phase transformations are one of the most fascinating phenomena in nature. Observing such transformations in real time and with the resolution of individual atoms could revolutionize our understanding of their chemical and physical processes. This research demonstrates that a novel crystal phase of FeGe₂ can be interfaced from two materials with vastly different physical properties: Fe₃Si, a ferromagnet, interfaced with amorphous germanium, a semiconductor. Terker and his colleagues were able to demonstrate that a hybrid sample preparation approach can yield thin samples suitable for high resolution HAADF STEM while at the same time retaining the sample composition and structure. This approach could be applied to many different heterostructures and lead to a much broader applicability of the in situ TEM method in the study of phase transformations.

Markus personal image improved

“For the atomic scale investigation of small nanostructures at high temperatures, the reduction of sample drift is of paramount importance. The new generation of DENSsolutions Wildfire Nanochips offer the ideal solution for this due to their small and reproducible bulging. Their robustness also enables an easy and safe transfer of the specimen lamella of any form or sample geometry.”

Markus Terker
PhD Student |  Paul-Drude-Institut in Berlin, Germany 

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Torsten feature image

Visualizing the structural evolution of thermally-decaying platinum nanowires

 

Using our Wildfire system, scientists gain an exceptional in-depth understanding of the morphological changes of platinum nanowires at certain temperatures

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Visualizing the structural evolution of thermally-decaying platinum nanowires

Visualizing the structural evolution of thermally-decaying platinum nanowires

Using our Wildfire system, scientists gain an exceptional in-depth understanding of the morphological changes of platinum nanowires at certain temperatures

Original article by Torsten Walbert, Falk Muench, Yangyiwei Yang, Ulrike Kunz, Bai-Xiang Xu, Wolfgang Ensinger, and Leopoldo Molina-Luna

Torsten feature image

The morphological transformation of a platinum nanowire as temperature increases and the two domain types observed

Metal nanowires represent a main class of one-dimensional nanomaterials and have been proven essential for a wide range of applications. Previous works on electrodeposited nanowires focused on ex situ SEM characterization, which is limited in terms of resolution and unable to monitor internal nanostructure changes. Using the DENSsolutions Wildfire system, Torsten Walbert and his colleagues from the Materials Analysis group and Prof. Leopoldo Molina-Luna from the Advanced Electron Microscopy (AEM) Division at the Institute for Materials Science, TU Darmstadt were able to investigate via in situ TEM the influence of temperature on polycrystalline platinum nanowires. Observing this process under remarkably high resolution enabled them to capture for the first time the internal transformations during both early and intermediate stages of the platinum nanowire decay. 

The structural evolution of nanowire decay 

Although nanowires are crucial for a wide range of applications, they are frequently prone to degradation. It is important that we understand these underlying failure mechanisms to better ensure reliable performance under operating conditions. Previous studies observing the thermal decay of nanowires have typically focused on ex situ investigations inside an SEM. Only a handful of studies look at the in situ characterization of nanowire decay using TEM, but even those focus specifically on gold nanowires. In this study, Torsten and his team observe the temperature influence on the degradation of platinum nanowires. Platinum is used due to its high mechanical, chemical and thermal stability as well as catalytic activity.

Below you can see an overview of the morphological transformation of a platinum nanowire after a thermal treatment between 250°C and 1100°C. It is observed that the main external transformation starts after 800°C, illustrated by the corresponding diameter evolution.

Structural evolution of pt nanowires

The morphological transformation of a platinum nanowire after thermal treatment and corresponding diameter evolution

Changes in internal nanostructure

Although external shape transformations occur after 800°C, changes in the internal nanostructure happen a lot earlier at markedly lower temperatures. As shown in the figure below, after heating to 250°C, no pronounced changes in the internal structure are observed compared to the initial state. After increasing the temperature to 450°C, the nanowire outline is still unaltered, but voids of low contrast (indicated by red circles) already start appearing. At 800°C, these voids begin to propagate and the shape slightly changes.

Further increasing the temperature to 850°C causes a grain boundary to extend, which is indicated by the dashed green line in the figure below. Finally, at 875°C, the grain boundary straightens while the voids increase and accumulate. Ultimately, these results confirm that internal nanowire restructuring considerably precedes the permanent changes of the outer nanowire shape. In fact, the observed faceted voids and grain boundaries are crucial factors guiding their transformation and final splitting, which is discussed in the next section.

TEM image showing the formation of voids (red circles) and straightening of grain boundary (green dashed line) at low and high temperatures

TEM video showing a void disappearing from a single-crystalline wire segment

Two surprising domain types

Some surprising results are observed after when the temperature goes beyond 875°C. Interestingly, the nanowires segregated into two domain types, one being single-crystalline and essentially void-free, while the other preserves void-pinned grain boundaries. This is the first time in academia that researchers observe this type of segregation, as it was neither described in previous experimental studies nor predicted by simulations.

You can see in the simulation and TEM video below that the wire separates into two domains, a single-crystalline domain and void-containing domain. Whereas the single-crystalline areas exhibit fast platinum transport, the void-containing areas show an unexpected morphological stability, retaining their nanostructure even at temperatures above 1000°C. In fact, the subsequent splitting of the nanowires is only observed in single-crystalline areas and thus leads to the formation of fragments with varying lengths and diameters. 

A simulation of the platinum nanowire disintegration, showing the curvature-driven mass transfer dominating the nanowire transformation

TEM video showing the disintegration of a platinum nanowire into two fragments

Novelty in findings

Performing in situ TEM in a controlled temperature environment represents a powerful approach for investigating the structural transformations of metal nanowires. Obtaining detailed insights into the internal nanostructure of nanowires and their evolution over time would otherwise be impossible without in situ TEM. Torsten and his team were able to relate the onset of shape changes to distinct nanostructural features acting as starting points in the disintegration process. This study is not only of great interest for basic research, but also helps in predicting the thermal robustness and reliability of nanowires in devices and can serve as a synthetic tool, enabling the control over the disintegration sequence via defect engineering. If we can understand the mechanism behind the process of decomposition, we can better predict and control the thermal stability of nanowires, adapting their shape and properties according to specific applications and conditions. 

Walbert, Torsten portrait -400 px

“The DENSsolutions Wildfire chip enabled an exact and fast temperature regulation with a homogeneous heat distribution, allowing us to investigate the decomposition process of Pt nanowires in situ. Without it, it would not have been possible to follow the transformations of the nanowires directly and to link them to the internal changes in the nanostructure.”

 

Torsten Walbert
PhD Student | Technische Universität Darmstadt

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Dental crown created by selective laser melting (SLM)

Improving the mechanical properties of 3D printed metal parts

 

Using our Wildfire system, researchers explore the microstructural changes occurring in AlSi10Mg during 3D printing and post processing

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The first direct observation of pharmaceutical non-classical crystallization

The first direct observation of pharmaceutical non-classical crystallization

Using the Ocean system, scientists achieve supersaturation in LPEM experiments, revolutionizing pharmaceutical crystallization

 

Original article by Jennifer Cookman, Victoria Hamilton, Simon Hall and Ursel Bangert

LPEM video showing the pre-crystallization process of flufenamic acid

Whereas classical crystallization deals with layer-by-layer growth of crystals, non-classical crystallization (NCC) involves multiple different crystallization pathways towards the formation of final stable crystals. Although NCC has been widely documented in research, there is still much to be explored regarding the intermediate stages of crystallization and their direct observation. This is especially true for small organic molecules like flufenamic acid (FFA), an anti-inflammatory drug used for the treatment of rheumatic disorders.

Using the DENSsolutions Ocean LPEM system, Dr. Jennifer Cookman from the Bernal Institute in the University of Limerick and her colleagues were able to capture the intermediate pre-crystalline stages of this small organic molecule. This research marks the first ever direct observation of a pharmaceutical material undergoing NCC, highlighting the rising value and importance of in-situ TEM techniques in the pharmaceutical industry. 

The observed processes of NCC

Crystallization is a fundamental process that occurs in nature to produce some of the most common materials in daily life, such as the popular active pharmaceutical ingredient (API) ibuprofen or FFA. Properties such as solubility and bioavailability are linked to the crystal structure of the active compound. Considering APIs are commonly polymorphic, it is important to understand the intermediate stages of their crystallization. Specifically, if we can identify polymorphs with more desirable properties in the intermediate stages of crystallization, then this opens the door to harnessing and potentially directing their formation.

In this study, Dr. Cookman and her colleagues observed in situ the processes involved in the nanoscale crystallization of FFA. As illustrated in the figure below, this process involves four stages: aggregation, coalescence into a metastable entity, nucleus formation, and finally, crystallization.

A summary of the observed processes involved in the nanoscale crystallization of FFA

The researchers observed that FFA begins as a collection of small independent pre-nucleation clusters (PNCs). These PNCs are essentially stable particle clusters that form prior to the nucleation of a solid phase. They were able to follow three notable aggregates of PNCs that each followed the same transformational events. Particularly, after aggregation, these PNCs each independently coalesced, or merged, and formed a metastable phase. After this, the densification and development of a nucleus occurs, leading to the formation of FFA crystals. The processes of coalescence and densification will be further discussed and depicted below.

Coalescence

The aggregation of the PNCs were shown to have occurred prior to the researchers’ initial observations. Therefore the primary transformation observed for the three aggregates was actually that of coalescence. In the image below, you can see clearly that for each of the three selected aggregates, the individual clusters merge to form one cohesive entity after approximately 3 minutes.

A time-lapse of each of the three aggregates of PNCs undergoing coalescence

Densification towards crystallization

Following coalescence is the densification and development of a nucleus. This nucleus is formed by the successive sacrifice of surrounding material, leading to the formation of a new crystalline-like object, significantly more electron dense than before. Whereas coalescence took around 3 minutes, this densification occurred rapidly in under 10 seconds. The image and three videos below depict this rapid pre-crystallization process of FFA. 

A frame-by-frame summary of the three aggregates illustrating the pre-crystallization process of FFA

Aggregate 1

Aggregate 2

Aggregate 3

Novelty in findings

This research contributes academically in that the direct observations reported for the crystallization of FFA reveal insightful new information about the potential pathways towards crystallization. Moreover, it highlights the need to further investigate the nucleation and resulting crystallization of other small organic molecules via in situ techniques such as LPEM. LPEM presents itself as a required and complementary tool to not only comprehend but also probe chemistry at the nanoscale. This is true especially in regards to the crystallization of pharmaceutical ingredients, in which the development of the end product highly depends on controlling at the molecular building block level. 

The novelty of this research also lies in that it sheds light on the crystallization and nucleation of pharmaceutical products, providing the necessary information to further refine industrial-scale processes. If we can observe and understand the crystallization pathways that small organic molecular crystals like FFA take, we can better streamline production activities and develop effective manufacturing processes for generic drugs. It is precisely our goal at DENSsolutions to enable researchers like Dr. Jennifer Cookman to continue to bridge gaps in research using our solutions and uncover results that can impact this world, in the pharmaceutical industry and beyond.  

DENSsolutions Jennifer Cookman

“The DENSsolutions Ocean holder is a simple solution to native environment metrology that has the potential to revolutionize how we view pharmaceutical crystallization.”

 

“The DENSsolutions Ocean holder is a simple solution to native environment metrology that has the potential to revolutionize how we view pharmaceutical crystallization.”

Dr. Jennifer Cookman
Post Doctoral Researcher | University of Limerick

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