Category Technology/Electronics

Exciton Fission: One Photon in, two Electrons out

Emergence of the bitriplet exciton in crystalline pentacene.
Emergence of the bitriplet exciton in crystalline pentacene.
© TU Berlin

Photovoltaics, the conversion of light to electricity, is a key technology for sustainable energy. Since the days of Max Planck and Albert Einstein, we know that light as well as electricity are quantized, meaning they come in tiny packets called photons and electrons. In a solar cell, the energy of a single photon is transferred to a single electron of the material, but no more than one. Only a few molecular materials like pentacene are an exception, where one photon is converted to two electrons instead.

“When pentacene is excited by light, the electrons in the material rapidly react,” explains Prof. Ralph Ernstorfer, a senior author of the study...

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Engineers ‘Grow’ Atomically Thin Transistors on Top of Computer Chips

Engineers 'grow' atomically thin transistors on top of computer chips
Uniformity characterization of the 200 mm monolayer MoS2 synthesized at low temperature. Credit: Nature Nanotechnology (2023). DOI: 10.1038/s41565-023-01375-6

Emerging AI applications, like chatbots that generate natural human language, demand denser, more powerful computer chips. But semiconductor chips are traditionally made with bulk materials, which are boxy 3D structures, so stacking multiple layers of transistors to create denser integrations is very difficult.

However, semiconductor transistors made from ultrathin 2D materials, each only about three atoms in thickness, could be stacked up to create more powerful chips...

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Using Quantum Physics to Secure Wireless Devices

Using quantum physics to secure wireless devices
Physically unclonable function (PUF) based cryptographic keys generated by the PT-symmetric electronic system. a Illustration of the PUF-enabled secure radio-frequency (RF) authentication and communication. b Generation of the challenge-response pair (CRP) and the cryptographic key in the proposed PUF system. Our experiments utilize the pulse excitation shown in the left panel of b, and the response, represented by the transient voltage signal measured across the reader’s capacitor, and its discretized form are shown in the middle and right panels of b, respectively. After proper sampling and processing, the analog response is converted to a digital key composed of a bitstring. Credit: Nature Communications (2023). DOI: 10.1038/s41467-023-36508-x

From access cards and key fobs to Blu...

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Transforming Highways for High-Speed Travel and Energy Transport

Schematic illustration of the superconducting highway for energy transport and storage and superconductor levitation for the transport of people and goods. Credit: Vakaliuk et al.
Schematic illustration of the superconducting highway for energy transport and storage and superconductor levitation for the transport of people and goods. Credit: Vakaliuk et al.

Revolutionary design could combine superconductor levitation, lossless electricity transmission, and liquid hydrogen transportation into one system. Superconductors can conduct electricity without any resistance or power loss, and they can effortlessly cause magnets to levitate above them. These properties would make superconductors useful for high-speed trains or long-distance power transmission, except for one glaring problem: superconductors only work at low temperatures, more than a hundred degrees below zero.

This one requirement makes building a hyperefficient electrical grid or high-speed rail netwo...

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