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​The shift to a future marked by carbon-free renewable energy sources is being explored by KAUST researcher Min Suk Cha as societies seek to end our reliance on fire. Cha and his team, including postdoc Ramses Snoeckx are researching electrically generated plasmas as the future of chemical synthesis and manufacturing to replace combustion-driven processes.

"The importance of fire—its acquisition, control or theft—is a recurring theme in the mythologies of cultures across the globe," says Cha, from the Clean Combustion research center. Fire provided our ancestors with the means to cook, heat, hunt, create and protect. Over time, our reliance on fire has only grown. "Since the industrial revolution, combustion has become the foundation of power generation, transportation, smelting and material processing," says Cha. "This was followed rapidly with advances in petrochemistry, producing fertilizers; materials, such as plastics; medicine; and much more."

The downside of fire has become all too clear as the climate-altering side effects of the CO₂ emissions it generates. "But renewable electricity offers a pathway forward," Cha says. Wherever fire has led, electricity has followed, he notes. "Even though we cannot abandon fossil fuels entirely just yet because of energy demands, a controlled transition from the era of fire to an electrified future appears imperative," Cha says.

Electric potential

As energy production shifts from fossil fuel combustion to renewable alternatives, the chemical industry could also transition from combustion-driven to renewables-driven processes. Rather than simply using renewable electricity as an alternative heat source, Cha is investigating a potentially more efficient alternative: directly applying a voltage to the chemical starting materials to trigger new chemical production by generating a plasma. "Plasma technology provides us with the opportunity to utilize the full potential of electrical energy," Cha says.

Plasma-driven reactions often emit light as components in the mixture shed energy following electron impacts© 2020 Ramses Snoeckx

Plasma is often described as the fourth state of matter, in line with solid, liquid and gas. A plasma is a gas in which some or all of the consistent molecules have had electrons ripped free, forming a complex cocktail of electrons, ions, atoms and molecules. Plasmas are common in the natural world, from the center of stars to lightning strikes. They can also be generated and maintained artificially by applying a strong electric field for example. The field accelerates the free electrons, which then canon into other molecules in the mixture, knocking free further electrons to sustain the plasma.

A direct strike by a speeding electron on a molecule can knock another electron free—or it can crack the molecule apart. A water molecule, for example, can split into a hydrogen radical and a hydroxyl radical. "We want to use this type of dissociation as a source of chemical reaction," Cha explains. Although water molecules or CO₂ molecules could be split by heating, it would require a huge amount of energy to heat up the whole gas sample. Using an electric field to accelerate electrons is a far more energy-efficient approach. "We can selectively transfer the electrical energy into the motion of charged particles."

One application of plasma chemistry the team is exploring is to crack apart CO₂ molecules, as the first step in turning captured CO₂ emissions into valuable chemicals.¹ By feeding a mixture of methane and CO₂ into a plasma reactor, researchers can trigger a reaction called dry reforming, which turns the two starting gases into hydrogen and carbon monoxide. This mixture, known as syngas, is a major chemical feedstock used in synthetic liquid fuel production, for example.

Plasma-driven molecular dissociation can also be used for hydrocarbon reforming, taking basic chains of carbon and hydrogen atoms and turning them into something more valuable.² "For example, I could turn CO₂, water and an alkane (a basic hydrocarbon) into an alcohol, an alternative fuel," Cha says.

Control reaction

"The great challenge with plasma-driven chemistry," says Cha, "is maximizing the yield of the desired product from the cocktail of reactive species generated under plasma conditions. My research is focused on how to control the plasma chemistry to make certain target chemicals," he says.

Bubbling reactant gases through an oil or liquid hydrocarbon, such as octane, under plasma reforming conditions can convert the basic hydrocarbon into value-added products.© 2020 Xuming Zhang and Min Suk Cha.

One advantage of plasma-driven over conventional chemistry is that researchers have two independently adjustable ways to supply the reaction with energy. They can separately alter the starting temperature of the reactant gases and the electrical energy applied to accelerate the free electrons in the mixture. "We have shown that electron impact reactions can initiate a chemical reaction regardless of initial conditions, and it is the thermochemistry, governed by the gas temperature, that has a dominant effect on product selectivity," Cha says. "Combining plasma with a catalyst can also improve reaction selectivity," he adds.

"Once control over product formation and selectivity for plasma processes is fully understood, this could pave the way for using plasmas for the on-demand production of tailored chemicals and fuels using renewable electricity," Cha says. Plasmas are already used industrially to manufacture computer chips, he adds. "The transition toward an electrified future is already kindling and we must prepare ourselves for the challenges and opportunities that electrification presents."

Humanity's transition from combustion to electricity may seem a very modern story, but our recognition of electricity's superiority over fire has a long history. "The Greek God Zeus, who punished Prometheus for giving fire to humankind, symbolized his might through lightning—which, of course, is electricity," Cha says. Not just electricity, but an electrically generated plasma.

-KAUST Discovery 

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​Congratulations to the KAUST Society of Petroleum Engineers (SPE) Chapter who were recently awarded the Student Chapter Excellence Award for 2020. This prestigious award is the second highest honor a student chapter may receive and is awarded to only 20% of student chapters around the world. The award is in recognition of the student chapter's programs in industry engagement, operations and planning, community involvement, professional development, and innovation.

Formed in 2011, The KAUST SPE Student Chapter is a graduate student group, which follows the Mission and Vision of the Society of Petroleum Engineers (SPE).  The Group has received a total of four awards since its inception.

KAUST SPE Student Chapter enables member students to enrich their fundamental knowledge by participating in frequently organized technical webinars and soft-skills events. 

Despite the difficulties faced this year, through the continuous commitment of students and support of faculty members from KAUST, the members continued to fulfill SPE's mission and to strive towards success in the future.

SPE's Board Meeting (during Covid-19) (from Left to Right: Ryan, Marcelo, Antonia, Akbar, Teyyuba, Ruben, Prof. Hussein Hoteit (Faculty Advisor), Elmir and Natalia (SPE President 2020))

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​Core Labs Reopening information

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​A novel technique for mass-producing better-performing perovskite-based solar cells could lay the foundations for next-generation devices that have more efficient power than currently available technologies.     

Perovskite solar cell (PSC) technologies have been shown to be dramatically more efficient compared with conventional, single-crystal silicon solar cells. In particular, thin-film halide PSCs have unique characteristics that make them ideal for photovoltaics. These include structural and optoelectronic properties, such as a high degree of crystalline order, a tunable bandgap and a high optical absorption coefficient.

These properties allow them to achieve power conversion efficiencies of more than 25 percent. They also make them attractive as top cells for tandem applications that use crystalline silicon substrates and could lead to PSCs with higher efficiencies.

However, the silicon surface, which usually contains micrometer-sized pyramidal structures, must be entirely covered by the perovskite to achieve these efficiencies, but achieving this coverage has proved very challenging.

Now, Erkan Aydin and Michele De Bastiani, from the KAUST Solar Center, working with scientists from the University of Toronto, Canada, and the National Renewable Energy Laboratory, U.S., have developed an innovative technique for depositing the perovskite onto the textured layer of silicon solar cells.

The technique is scalable for mass production and also enhances the optoelectronic properties compared to conventional perovskite-silicon tandems.

"Conventional solar cells employ only one semiconductor to convert sunlight into electricity, but their theoretical efficiency is limited to around 33 percent," explains Aydin. "By stacking two semiconductors in a 'tandem' solar cell, as we did, using halide perovskites and silicon, this limit can be pushed to 44 percent."

The researchers combined a solution-processed, micrometer-thick, wide-bandgap perovskite solar cell with the pyramidal-textured layer of silicon, which filled the gaps in the silicon surface without hampering the photovoltaic properties of the perovskite and produced a tandem perovskite/silicon solar cell with an efficiency of 25.7 percent.

"Previously, the silicon surface had to be flat polished to accommodate the perovskite layer, which greatly increased the cost of mass production," says Aydin.

The work could help to scale up the production of tandem PSCs with significantly enhanced performance, allowing researchers to work on perovskite/silicon tandem solar cells that are already the industrial standard, rather than working with platforms that cannot be mass produced.

"Our next step is to scale up our perovskite deposition technology to meet the current industrial size standards of the devices, first as a proof of concept, and then to pilot-line scale at a later stage," says De Bastiani.

-KAUST Discovery 

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​On a picturesque stretch of the Red Sea coast, Saudi Arabia is planning a new, fully automated megacity called NEOM. The new city is a futuristic global hub for education, healthcare, culture, business and technology based on renewable energy and green infrastructure. KAUST researchers have now completed the first comprehensive, high-resolution assessment of air quality for the region, and the results are promising.

Short for Neo-Mustaqbal, meaning "new future," NEOM is s a 500 billion USD initiative, dubbed "the world's most ambitious project." It is located in northwestern Saudi Arabia near the borders with Jordan and Egypt. Understanding the air quality and meteorological conditions over the NEOM development area is crucial for effectively monitoring and controlling air pollution for the megaproject."

NEOM is located in northwestern Saudi Arabia near the borders with Jordan and Egypt, adjacent to the Gulf of Aqaba.

© Astromujoff/ The Image Bank / Getty Images Plus

Air quality is affected by many factors, including wind direction and variability, sources of pollution and dust, and atmospheric conditions. However, in regions with sparse air quality measurements, such as the northern Red Sea coast, it is challenging to model air quality and develop an understanding of the processes by which airborne pollutants are accumulated and dispersed.

"The availability of reliable meteorological data and air pollutant concentrations over the NEOM region was the main challenge we faced in conducting our analysis," says research scientist Hari Dasari. "For this study we conducted a four-month air-quality monitoring campaign across five locations in 2018then performed numerical model simulations at very high resolution using grid cells of just 600 meters. This required enormous computational resources, for which we were fortunate to be able to rely on KAUST's SHAHEEN high-performance computational facility."

By running the model with known regional pollution sources over a simulated three-year period and comparing the model results with observed data, the researchers could derive the meteorological conditions across the project area and the principal drivers of pollution dispersion.

"We found that the air quality over NEOM is generally very good, although natural dust storms in summer can occur," says Dasari.

Led by Ibrahim Hoteit, the research team also found that differential heating over land and sea drives changes in wind direction, generating land and sea breezes that play a major role in dispersing pollutants in the NEOM region.

"As the first study of air quality in the NEOM region, our work provides valuable information on air quality and meteorological conditions that will be used by NEOM's planners and designers to minimize the accumulation of pollutions, the formation of heat islands and local wind jets," says Hoteit. 

-KAUST Discovery

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​Some of the fastest video cameras ever developed have been used by KAUST researchers to clarify how molecular-scale changes to water surfaces may impact the performance of industrial-scale purifications.

One factor that influences the stability of emulsions is how quickly small bubbles or droplets join together into larger droplets. Ivan Vakarelski, a research scientist in Sigurdur Thoroddsen's lab, notes that this type of coalescence is driven by variables ranging from bubble size, collision speed, and the "freedom" of molecules located at liquid surfaces.

"When liquids contact a solid, they tend to stick due to strong molecular forces. In contrast, a clean liquid exposed to air can move along relatively easily—we call that a mobile interface," explains Vakarelski. "It's a fundamental property that determines the behavior of many foams and emulsions."

Recently, Thoroddsen and his team used their expertise at high-speed imaging to observe collisions between air bubbles formed in a perfluorocarbon, a liquid with similar viscosity to water that can be refined to an ultrapure state. To their surprise, these bubbles did not coalesce as fast as anticipated. Instead, the high mobility of the air- perfluorocarbon interface caused the bubbles to repeatedly bounce off each other before merging.

In their latest work, the KAUST researchers broadened their investigations to the world's most important liquid—water. A clean air-water interface is supposed to be mobile, however, numerous studies suggest they have low molecular freedom because they are highly susceptible to contamination.

To resolve this quandary, Vakarelski helped design an experiment that used thin films of fatty acids to completely immobilize a free water surface. Then, they released millimeter-sized air bubbles that floated to the interface and crashed into it. When images of the rebounding bubbles were compared to ones taken on purified water surfaces, the team saw that the fatty acid film drastically reduced the degree of bouncing.

"A common belief is that once water is exposed to the atmosphere in a laboratory, it's impossible to keep it clean enough to be mobile," says Vakarelski. "However, our study shows that this is not correct—a standard purification device produces an interface that bounces bubbles back quite strongly."

Successful tests of this approach with other liquids, such as ethanol, indicate that bubble analysis could help solve problems in food processing applications as well as chemical production.

-KAUST Discovery

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​Better understanding the science that underpins well-known techniques for developing quantum dots—tiny semiconducting nanocrystals—can help reduce the guesswork of current practices as material scientists use them to make better solar panels and digital displays.


Just billionths of a meter across, quantum dots are routinely prepared in solution and coated or sprayed as an ink to create a thin electrically conducting film that is used to make devices. "But finding the best way to do this has been a matter of trial and error,” says material scientist Ahmad R. Kirmani. Now, with colleagues at KAUST and the University of Toronto, Canada, he has revealed why certain well-known techniques can dramatically improve the film’s performance.


Quantum dots absorb and emit different wavelengths of light depending on their size. This means they can be tuned to be highly efficient absorbers in solar panels, or to emit different colors for a display, just by making the crystals bigger or smaller.


The dots are commonly grown from lead and sulfur in solution. Because the dots’ properties depend on their size, their growth must be halted at the right point, which is done by adding special molecules to cap their growth. Engineers often use molecules of oleic acid, each with 18 carbon atoms, which attach to the crystal’s surface, like hairs, blocking growth. 


This creates a solution of dots suitable for coating to create a film. Yet, this film is not good at conducting electricity because the long acid molecules hamper the flow of electrons between nanocrystals. So engineers add shorter molecules. These “linkers” only have around two carbon atoms per molecule. The linkers replace the long capping molecules, increasing conductance. "The method has been used for a couple of decades, but nobody had investigated exactly what happens," says Kirmani. 


To find out, Kirmani’s team used a microbalance to monitor the exchange of oleic acid for linkers during the transition. They measured the spacing between the dots by scattering X-rays from them, and they also recorded the film’s changing thickness, density and optical absorption characteristics.  


Rather than seeing a smooth change in the film’s properties, they saw a sudden jump—marking a phase transition. When roughly all the acid molecules have been displaced by linkers, the dots abruptly come close together, and the conductivity shoots up. 


Kirmani hopes other teams will be inspired to investigate further, possibly by arresting the transition process somewhere midway and introducing various molecules to the dot surface to see what novel features emerge. “There is a lot of potential in taking this understanding to new paradigms for new technologies,” he says. 

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​"Extrapolating future climate trends from historical data is more challenging for enclosed seas than it is for open oceans and should be done with extreme caution," according to KAUST ocean modeling expert Ibrahim Hoteit. The finding follows detailed data reanalyses and computer simulations on wind and wave conditions over the Red Sea.

Hoteit and a team of researchers in Saudi Arabia, Italy and Ecuador examined high-resolution global datasets to identify and simulate wind and wave trends over the Red Sea since 1979. They then conducted advanced statistical analyses on lower-resolution data extending back to the beginning of the 20th century to investigate the influence of various global trends on the ones identified in the Red Sea.

“This allowed us to identify potential links with established climate patterns and quantify their influence on the trends identified from the high-resolution data,” explains KAUST research scientist Sabique Langodan.

The team found that the northern part of the Red Sea was demonstrating a clear reduction in the number and intensity of wind and wave events entering it from the Mediterranean since 1979. Further analyses found that this reduction is likely linked to a 70-year cycle in the North Atlantic, known as the Atlantic multidecadal oscillation (AMO). This cycle is expected to shift in the next 30 years, which could suggest that, rather than a continuing decreasing trend, northern Red Sea events will witness a shift, by slowing down or beginning to increase in the coming decades.

Wind and wave conditions in the southern part of the Red Sea are influenced by the winter monsoons from the Arabian Sea. These monsoons, however, are not yet predictable over the long term like the North Atlantic system. Based on their analyses, Hoteit and his colleagues expect that wind and wave conditions in this part of the Red Sea will vary randomly, with their intensity depending on the characteristics of the monsoons.

“It is reasonable to expect that our approach for analyzing trends over the Red Sea could be applied to other enclosed basins as long as it is possible to decompose the various dominant components of climate variability affecting them,” says Langodan.

The team next aims to further understand how large-scale climate variability influences physical and biological interactions within the Red Sea and what are their implications for the basin’s unique marine ecosystem. They also hope that a better understanding of the northern Red Sea climate will help in the design of wind energy farms for the Kingdom’s megacity, NEOM, which is being developed in the area.  

-KAUST Discovery