Category Physics

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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‘Raw’ data show AI Signals Mirror how the Brain Listens and Learns

University of California, Berkeley, researchers have measured brain waves in participants and artificial intelligence systems — a comparison they say provides a window into what is considered a black box of AI. (Photo courtesy iStock)

University of California, Berkeley, researchers have measured brain waves in participants and artificial intelligence systems – a comparison they say provides a window into what is considered a black box of AI.

New research from the University of California, Berkeley, shows that artificial intelligence (AI) systems can process signals in a way that is remarkably similar to how the brain interprets speech, a finding scientists say might help explain the black box of how AI systems operate.

Using a system of electrodes placed on participants’ heads,...

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Nifty Nanoparticles help ‘Peel back the Curtain’ into the world of Super Small Things

Physicists at The Australian National University (ANU) are using nanoparticles to develop new sources of light that will allow us to “peel back the curtain” into the world of extremely small objects – thousands of times smaller than a human hair – with major gains for medical and other technologies.

The findings, published in Science Advances, could have major implications for medical science by offering an affordable and effective solution to analyse tiny objects that are too small for microscopes to see, let alone the human eye. The work could also be beneficial for the semiconductor industry and improving quality control of the fabrication of computer chips.

The ANU technology uses carefully engineered nanoparticles to increase the frequency of light that cameras and ...

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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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