“Grätzel” Solar Cells achieve a New Record

Grätzel cells installed at the SwissTech Convention Center (credit: Alain Herzog)
Scientists at EPFL have increased the power conversion efficiency of dye-sensitized solar cells (“Grätzel cells”) beyond 15% in direct sunlight and 30% in ambient light conditions.

Mesoscopic dye-sensitized solar cells (DSCs) were invented in 1990s by Brian O’Regan and Michael Grätzel, taking on the latter’s name – the world-famous Grätzel cells. DSCs convert light into electricity through photosensitizers – dye compounds that absorb light and inject electrons into an array of oxide nanocrystals which subsequently are collected as electric current.

In DSCs, photosensitizers are attached (“adsorbed”) to the surface of nanocrystalline mesoporous titanium dioxide films that are imbibed with redox active electrolytes or a solid charge-transport material – the entire design aims...

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Magma on Mars likely

Colour-coded topographical view of the Cerberus Fossae features: reds and whites are relatively higher than blues and purples. (Photograph: ESA/DLR/FU Berlin)

Until now, Mars has been generally considered a geologically dead planet. An international team of researchers now reports that seismic signals indicate vulcanism still plays an active role in shaping the Martian surface.

Since 2018, when the NASA InSight Mission deployed the SEIS seismometer on the surface of Mars, seismologists and geophysicists at ETH Zurich have been listening to the seismic pings of more than 1,300 marsquakes. Again and again, the researchers registered smaller and larger Mars quakes. A detailed analysis of the quakes’ location and spectral character brought a surprise...

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Fighting Tumours with Magnetic Bacteria

Illustration of a blood vessel as well as the blood cells and the magnetic bacteria
Magnetic bacteria (grey) can squeeze through narrow intercellular spaces to cross the blood vessel wall and infiltrate tumours. (Visualisations: Yimo Yan / ETH Zurich)

Researchers at ETH Zurich are planning to use magnetic bacteria to fight cancerous tumours. They have now found a way for these microorganisms to effectively cross blood vessel walls and subsequently colonise a tumour.

Scientists around the world are researching how anti-cancer drugs can most efficiently reach the tumours they target. One possibility is to use modified bacteria as “ferries” to carry the drugs through the bloodstream to the tumours. Researchers at ETH Zurich have now succeeded in controlling certain bacteria so that they can effectively cross the blood vessel wall and infiltrate tumour tissue.

L...

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Scientists discover Exotic Quantum State at Room Temperature

Quantum Hall effect

For the first time, physicists have observed novel quantum effects in a topological insulator at room temperature. This breakthrough, published as the cover article of the October issue of Nature Materials, came when Princeton scientists explored a topological material based on the element bismuth.

The scientists have used topological insulators to demonstrate quantum effects for more than a decade, but this experiment is the first time these effects have been observed at room temperature. Typically, inducing and observing quantum states in topological insulators requires temperatures around absolute zero, which is equal to -459 degrees Fahrenheit (or -273 degrees Celsius).

This finding opens up a new range of possibilities for the development of efficient quantum technologies, ...

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