Dopant boosts carbon nanotubes’ conductivity tenfold

Good news!

"Doping carbon nanotubes with tetrachloroaluminate ions can increase their electrical conductivity around tenfold without harming the nanotube structures, researchers in Spain have shown. The research helps explain the chemistry of nanotube doping, and could potentially lead to applications such as lighter, stronger cables for electricity distribution. ...

exposed commercial double-walled carbon nanotubes with an initial conductivity of around 1.4MS/m to an atmosphere of aluminium trichloride and excess chlorine for 24 hours, causing tetrachloroaluminate ions to diffuse into the structure. Spectroscopic analysis indicated that, rather than entering the nanotubes’ centres, the ions intercalated between the walls. The researchers observed no significant expansion of the nanotubes. They showed that the fact that the nanotubes are wrapped concentrically creates a greater gap between the carbon atoms than in multilayer graphene, ... ‘Therefore, it can host the dopant without distorting the bundle.’ ..."

From the editor's summary and abstract:

"Editor’s summary

Translating the outstanding individual properties of carbon nanotubes, such as their electrical and thermal conductivity, into bulk materials that retain those properties remains a challenge.

de Isidro-Gomez et al. demonstrated controlled vapor-phase intercalation of tetrachloroaluminate (AlCl₄−) ions within intertube channels to make macroscopic double-walled carbon nanotube fibers.

The fibers showed high electrical conductivity approaching 40% of the value of copper at room temperature.

On a per-weight basis, the cables exceeded both the conductivity and strength of conventional overhead cables. Furthermore, they showed excellent dry stability and reasonable moisture tolerance when protected by a polymer sheath. ...

Abstract

Translating the conductivity of individual carbon nanotubes into practical, macroscopic conductors remains a challenge.

We report highly aligned fibers of double-walled carbon nanotubes intercalated with chains of tetrachloroaluminate anions (AlCl4−) in the intertube channels. The AlCl4− intercalant acts as a noncovalent dopant, accepting 0.65 electrons per anion, mostly from the outer nanotube layer.

Combined with a 17% intercalant volume fraction, it produces an increase in room-temperature conductivity to values as high as 24.5 mega-Siemens per meter, which is 41% of that of copper.

Specific conductivity values reach 17,345 Siemens-meter squared per kilogram, which is superior to that of metals.

These fibers are five times stronger and half the weight of conventional overhead cables while remaining stable in dry conditions and retaining 80% of their conductivity protected from moisture by a cable polymer sheath."

Dopant boosts carbon nanotubes’ conductivity tenfold | Research | Chemistry World

Intercalated carbon nanotube fibers with high specific electrical conductivity (no public access)

The tetrachloroaluminate ions are positioned in interstitial channels between the double-walled carbon nanotubes

AI-driven framework uncovers new carbon structures—one thought to be harder than diamond

Amazing stuff! The magic of carbon!

"... With this approach, the researchers discovered several allotropes with combinations of exotic properties that have never previously been observed. Among them is a superhard phase with a calculated hardness exceeding even that of diamond. Its dense sp3-dominant network makes it a potentially groundbreaking material for applications demanding extreme hardness.

On top of this already remarkable discovery, the team discovered a material whose thermal conductivity varies depending on the direction of heat flow, combined with an ultra-low shear stiffness—allowing different regions of the carbon lattice to reorient relative to each other when a shear force is applied.

"We also discovered an sp-sp2-sp3 hybridized phase of C12 phase containing 12 carbon atoms per unit cell, which uniquely combines metallic conductivity with a negative Poisson's ratio," ... The latter property describes how the material counterintuitively expands in a direction perpendicular to the direction in which it is being stretched. ..."

From the abstract:

"The discovery of novel carbon allotropes with tailored thermal and mechanical properties is critical for advanced thermal management. However, exploring the vast configurational space of carbon using ab initio calculations remains computationally prohibitive. Driven by the rich topological landscape of carbon, where the competition between  and hybridization states dictates material performance, we establish a closed-loop artificial intelligence (AI) framework to explore this complex configurational space. We introduce a hybridization entropy descriptor to guide the search beyond conventional forms.

Here, we establish a closed-loop AI framework that synergizes a Large Language Model (LLM) for structural generation with a Machine Learning Potential (MLP) for accelerated evaluation. Leveraging CrystaLLM to generate candidates and an iteratively refined MLP for high-fidelity validation, we screened thousands of structures to identify several stable allotropes with exotic properties.

Specifically, we report “yne-diamond C12” and “yne-hex-diamond C8,” which exhibit extreme thermal anisotropy and ultralow in-plane shear stiffness arising from their mixed sp– hybridization.

Furthermore, we discovered a complex sp– –  hybridized C12 phase that combines metallic conductivity with an anomalous negative Poisson's ratio.

Notably, we identified a superhard phase (C16_3) possessing a calculated Vickers hardness (103.3 GPa) exceeding that of diamond {96 GPa  ...

Microscopic analysis reveals that thermal transport in these materials is governed by the interplay between rigid frameworks and flexible linkers. This work expands the known carbon phase space and demonstrates the efficacy of coupling generative AI with MLPs for the accelerated inverse design of functional materials."

AI-driven framework uncovers new carbon structures—one thought to be harder than diamond

LLM-driven discovery for carbon allotropes with bond-network entropy (no public access)

Chinese researchers say they’ve created the first pure samples of hexagonal diamond, Known as the ultimate semiconductor

Amazing stuff!

"Chinese researchers say they’ve created the first pure samples of hexagonal diamond, a superhard mineral previously found only in meteorites, that outperforms natural diamond in hardness and heat resistance."

From the abstract:

"Known as the ‘ultimate semiconductor’, cubic diamond (CD) has gained substantial interest both scientifically and industrially. Its polymorph, hexagonal diamond (HD), is even more intriguing because of its fascinating properties associated with the meteorite impacts. As no solid experimental evidence has been provided to prove its existence, the physical properties of HD remain largely unexplored.

Here we report the synthesis of millimetre-sized, phase-pure HD from highly oriented pyrolytic graphite (HOPG) compressed along the c-axis at elevated temperatures. Combining advanced structural characterizations and theoretical simulations, we confirm the identity of HD and clarify the transformation pathway from graphite. Bulk HD exhibits a slightly higher hardness than CD and high thermal stability. These findings resolve the long-standing controversy on the existence of HD as a discrete carbon phase and provide new insight into the graphite-to-diamond phase transition, paving the way for future research and practical use of HD in advanced technological applications."

Monday, March 16, 2026 - Join The Flyover

In physics first, Chinese scientists create rare 'hexagonal diamond' that's harder than natural diamond

Bulk hexagonal diamond (no public access)

Fig. 2: Atomic structure of the bulk HD recovered from 20 GPa and 1,300 °C.

Diamond Thermal Conductivity: A New Era in Chip Cooling

Amazing stuff! Diamonds are a chip's best friend!

"When you grow a micrometers-thick layer of diamond inside advanced chips, it spreads out the heat and drops the temperature more than 50°C."

"... But with great power comes great…heat! ...

In some ways, diamond is ideal. It’s one of the most thermally conductive materials on the planet—many times more efficient than copper—yet it’s also electrically insulating. However, integrating it into chips is tricky: Until recently we knew how to grow it only at circuit-slagging temperatures in excess of 1,000 °C.

But my research group at Stanford University has managed what seemed impossible. We can now grow a form of diamond suitable for spreading heat, directly atop semiconductor devices at low enough temperatures that even the most delicate interconnects inside advanced chips will survive. To be clear, this isn’t the kind of diamond you see in jewelry, which is a large single crystal. Our diamonds are a polycrystalline coating no more than a couple of micrometers thick."

Diamond Thermal Conductivity: A New Era in Chip Cooling - IEEE Spectrum "A micrometers-thick integrated layer spreads out the heat"

Gallium nitride high-electron-mobility transistors were an ideal test case for diamond cooling. The devices are 3D and the critical heat-generating part, the two-dimensional electron gas, is close to the surface.

Polycrystalline diamond could help reduce temperatures inside 3D chips. Diamond thermal vias would grow inside micrometers-deep holes so heat can flow from vertically from one chip to a diamond heat spreader in another chip that’s stacked atop it.

Liquid carbon reveals its secrets

Amazing stuff!

"Thanks to new experiments using the DIPOLE 100-X high-performance laser at the European X-ray ... Electron Laser (XFEL) ... has obtained the first detailed view of the microstructure of carbon in its liquid state. The work will help refine models of liquid carbon, enabling important insights into the role that it plays in the interior of ice giant planets like Uranus and Neptune, where liquid carbon exists in abundance. It could also inform the choice of ablator materials in future technologies such as nuclear fusion. ..."

"... Under normal pressure carbon does not melt but immediately changes into a gaseous state. Only under extreme pressure and at temperatures of approximately 4,500 degrees Celsius – the highest melting point of any material – does carbon become liquid. No container would withstand that.

Laser compression, on the other hand, can turn solid carbon into liquid for fractions of a second. And the challenge was to use these fractions of a second to take measurements. In a previously unimaginable way, this has now become reality at the European XFEL, the world’s largest X-ray laser with its ultrashort pulses, in Schenefeld, near Hamburg. ...

The unique combination of the European XFEL with the high-performance laser DIPOLE100-X was crucial for the success of the experiment. ... A community of leading international research institutions at the HED-HIBEF (High Energy Density) experimental station at European XFEL has now combined powerful laser compression with ultrafast X-ray analysis and large-area X-ray detectors for the first time.

In the experiment, the high-energy pulses of the DIPOLE100-X laser drive compression waves through a solid carbon sample and liquefy the material for nanoseconds ... During this nanosecond, the sample is irradiated with the ultrashort X-ray laser flash of the European XFEL. The carbon atoms scatter the X-ray light – similar to the way light is diffracted by a grating. The diffraction pattern allows inferences to be drawn about the current arrangement of the atoms in the liquid carbon.

The whole experiment only lasts a few seconds but is repeated many times: every time with a slightly delayed X-ray pulse or under slightly different pressure and temperature conditions. Many snapshots combine to make a movie. Researchers have thus been able to trace the transition from solid to liquid phase one step at a time. ..."

From the abstract:

"Carbon has a central role in biology and organic chemistry, and its solid allotropes provide the basis of much of our modern technology. However, the liquid form of carbon remains nearly uncharted, and the structure of liquid carbon and most of its physical properties are essentially unknown. But liquid carbon is relevant for modelling planetary interiors and the atmospheres of white dwarfs, as an intermediate state for the synthesis of advanced carbon materials, inertial confinement fusion implosions, hypervelocity impact events on carbon materials and our general understanding of structured fluids at extreme conditions.

Here we present a precise structure measurement of liquid carbon at pressures of around 1 million atmospheres obtained by in situ X-ray diffraction at an X-ray free-electron laser.

Our results show a complex fluid with transient bonding and approximately four nearest neighbours on average, in agreement with quantum molecular dynamics simulations.

The obtained data substantiate the understanding of the liquid state of one of the most abundant elements in the universe and can test models of the melting line.

The demonstrated experimental abilities open the path to performing similar studies of the structure of liquids composed of light elements at extreme conditions."

Liquid carbon reveals its secrets – Physics World

Structure of liquid carbon measured for the first time (original news release) "With the declared aim of measuring matter under extreme pressure, an international research collaboration headed by the University of Rostock and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) used the high-performance laser DIPOLE 100-X at European XFEL for the first time in 2023. With spectacular results: In this initial experiment they managed to study liquid carbon – an unprecedented achievement ... "

The structure of liquid carbon elucidated by in situ X-ray diffraction (open access)

Groundbreaking experiment at European XFEL: Research team measured structure of liquid carbon for the first time (illustration ...)

Fig. 1: Schematic of the experimental setup.

Scientists discover molecules (pyrene) that store much of the carbon in space

Amazing stuff!

"... researchers ... discovered that a distant interstellar cloud contains an abundance of pyrene, a type of large, carbon-containing molecule known as a polycyclic aromatic hydrocarbon (PAH).

The discovery of pyrene in this far-off cloud, which is similar to the collection of dust and gas that eventually became our own solar system, suggests that pyrene may have been the source of much of the carbon in our solar system. That hypothesis is also supported by a recent finding that samples returned from the near-Earth asteroid Ryugu contain large quantities of pyrene. ...

Due to its symmetry, pyrene itself is invisible to the radio astronomy techniques that have been used to detect about 95 percent of molecules in space. Instead, the researchers detected an isomer of cyanopyrene, a version of pyrene that has reacted with cyanide to break its symmetry. The molecule was detected in a distant cloud known as TMC-1, using the 100-meter Green Bank Telescope (GBT), a radio telescope at the Green Bank Observatory in West Virginia. ...

PAHs, which contain rings of carbon atoms fused together, are believed to store 10 to 25 percent of the carbon that exists in space. More than 40 years ago, scientists using infrared telescopes began detecting features that are thought to belong to vibrational modes of PAHs in space, but this technique couldn’t reveal exactly which types of PAHs were out there. ..."

From the abstract:

"Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent aromatic rings. Infrared emission bands show that PAHs are abundant in space, but only a few specific PAHs have been detected in the interstellar medium. We detect 1-cyanopyrene, a cyano-substituted derivative of the related four-ring PAH pyrene, in radio observations of the dense cloud TMC-1 using the Green Bank Telescope. The measured column density of 1-cyanopyrene is ... , from which we estimate that pyrene contains up to 0.1% of the carbon in TMC-1. This abundance indicates that interstellar PAH chemistry favors the production of pyrene. We suggest that some of the carbon supplied to young planetary systems is carried by PAHs that originate in cold molecular clouds."

Scientists discover molecules that store much of the carbon in space | MIT News | Massachusetts Institute of Technology "The discovery of pyrene derivatives in a distant interstellar cloud may help to reveal how our own solar system formed."

Detection of interstellar 1-cyanopyrene: A four-ring polycyclic aromatic hydrocarbon (no public access)

Diamond fused to sapphire and other materials might be the next big quantum thing

Amazing stuff! Possibly very useful!

"Scientists have fused a diamond to a sapphire. And to silicon, lithium, and a few other materials. ...

But diamond is also homoepitaxial – it only grows on other diamonds. This makes it much less useful. ...

it has very high electrical resistance, but it conducts heat very well. .. tiny defects called nitrogen vacancy centres which are ideal for hosting quantum systems. ...

The result is a diamond membrane, as small as 10 nanometres thick, neatly bonded to another substance. ..."

"Synthetic diamond is durable, inert, rigid, thermally conductive and chemically well-behaved—an elite material for both quantum and conventional electronics. But there’s one problem. Diamond only likes diamond. ...

By precisely engineering defects in the crystal lattice, researchers create durable qubits ideal for quantum computing, quantum sensing and other applications. ..."

From the abstract:

"Diamond has superlative material properties for a broad range of quantum and electronic technologies. However, heteroepitaxial growth of single crystal diamond remains limited, impeding integration and evolution of diamond-based technologies. Here, we directly bond single-crystal diamond membranes to a wide variety of materials including silicon, fused silica, sapphire, thermal oxide, and lithium niobate. Our bonding process combines customized membrane synthesis, transfer, and dry surface functionalization, allowing for minimal contamination while providing pathways for near unity yield and scalability. We generate bonded crystalline membranes with thickness as low as 10 nm, sub-nm interfacial regions, and nanometer-scale thickness variability over 200 by 200 μm2 areas. We measure spin coherence times T2 for nitrogen vacancy centers in 150 nm-thick bonded membranes of up to 623 ± 21 μs, suitable for advanced quantum applications. We demonstrate multiple methods for integrating high quality factor nanophotonic cavities with the diamond heterostructures, highlighting the platform versatility in quantum photonic applications. Furthermore, we show that our ultra-thin diamond membranes are compatible with total internal reflection fluorescence (TIRF) microscopy, which enables interfacing coherent diamond quantum sensors with living cells while rejecting unwanted background luminescence. The processes demonstrated herein provide a full toolkit to synthesize heterogeneous diamond-based hybrid systems for quantum and electronic technologies."

Diamond fused to sapphire might be the next big quantum thing

New diamond bonding technique a breakthrough for quantum devices (original news release) "New technique allows greater integration of synthetic diamonds, improving how both quantum and conventional electronics are built"

Direct-bonded diamond membranes for heterogeneous quantum and electronic technologies (open access)

Fig. 1: Schematics of the plasma-activated bonding of diamond membranes.

Fig. 2: Characterization of the bonded membrane.

Single-molecule switch is a million times faster than a transistor

Amazing stuff! Machine learning & AI depend on among other things on better & faster computers!

"... The researchers made a huge breakthrough that could be a game-changer in all tech industries by using fullerene to make a switch from a single molecule. The switching speed is insane, almost a million times faster than a classical computer.

This development could pave the way for the creation of computers beyond what is currently possible with electronic transistors. It could also lead to significant improvements in microscopic imaging, enabling researchers to scrutinize the physical world in unprecedented detail. ..."

From the abstract:

"Single-molecule electron sources of fullerenes driven via constant electric fields, approximately 1 nm in size, produce peculiar emission patterns, such as a cross or a two-leaf pattern. By illuminating the electron sources with femtosecond light pulses, we discovered that largely modulated emission patterns appeared from single molecules. Our simulations revealed that emission patterns, which have been an intractable question for over seven decades, represent single-molecule molecular orbitals. Furthermore, the observed modulations originated from variations of single-molecule molecular orbitals, practically achieving the subnanometric optical modulation of an electron source."

Single-molecule switch is a million times faster than a transistor The ultrafast electron switch could theoretically enable computations orders of magnitude faster than currently possible with classical transistors.

I believe this is the paper:

Light-Induced Subnanometric Modulation of a Single-Molecule Electron Source (open access)

FIG. 1. Conceptual diagram of ultrafast electron emissions from a nano-object by irradiating a light pulse

Schematic representation of a fullerene C60 molecule

‘Fullertubes’ Join the Family of Carbon Crystals

Very recommendable! Amazing stuff! Well written overview article!

So we still know little about water, carbon, and the carbon cycle, but are to believe the Global Warming Hoax and Climate Change Religion?

"... In 1985, they had their first answer. A group of chemists discovered little hollow spheres constructed of 60 carbon atoms that they dubbed buckminsterfullerenes, or buckyballs or fullerenes for short. (The crystals resembled geodesic domes, popularized by the architect R. Buckminster Fuller.) A new field of chemistry sprang up around the nanometer-wide spheres, as researchers raced to discover properties and applications of what’s been called the most beautiful molecule. ...
Then, a few years later, a paper by the Japanese physicist Sumio Iijima sparked interest in a related carbon form, initially dubbed buckytubes but now known as carbon nanotubes: hollow cylinders made of a honeycomb lattice of carbon atoms that’s rolled up like a toilet paper tube. ...
Then in 2004, the physicists Andre Geim and Konstantin Novoselov found a way to isolate flat sheets of carbon atoms — a crystal known as graphene ...
Recently, chemists discovered yet another type of carbon crystal ...
Fullertubes combine the best features of fullerenes and nanotubes. Or the worst of both. ...
In 2020, Stevenson and collaborators announced the first member of the fullertube family, a 90-atom molecule that’s essentially two halves of a buckyball connected by a 30-atom nanotube midsection. They found the molecule along with two larger siblings made of 96 and 100 carbon atoms, respectively. ...
This year, [2022], [researchers] described two more fullertubes, both consisting of 120 carbon atoms. Their studies show that the narrower of these pill-shaped molecules is electrically conductive, while the wider, shorter one is — intriguingly — a semiconductor, meaning it could potentially be used for transistors and other electronic devices. Fullertubes also have a range of optical and tensile properties that the researchers are still exploring. ..."

‘Fullertubes’ Join the Family of Carbon Crystals | Quanta Magazine The buckminsterfullerene revolution never came, but some researchers are eagerly exploring the properties of newfound carbon crystals known as fullertubes.

Steven Stevenson, a chemist ... holds a model of a fullertube, a kind of carbon crystal he discovered in 2020.