Category Technology/Electronics

This first version of a new layered perovskite solar cell already achieves an efficiency of more than 20 percent, rivaling many commercial solar cells. Flexible and easy to make, it can produce more than half a volt of electricity. Credit: Onur Ergen, UC Berkeley

Solar cells made from an inexpensive and increasingly popular material called perovskite can more efficiently turn sunlight into electricity using a new technique to sandwich 2 types of perovskite into a single photovoltaic cell. Perovskite solar cells are made of a mix of organic molecules and inorganic elements that together capture light and convert it into electricity, just like today’s more common silicon-based solar cells...

1. Schematics above show light input (green) entering opposite ends of a single device. When the phase of light input 1 is faster than that of input 2 (left panel), the gain medium dominates, resulting in coherent amplification of the light, or a lasing mode. When the phase of light input 1 is slower than input 2 (right panel), the loss medium dominates, leading to coherent absorption of the input light beams, or an anti-lasing mode. (Credit: Zi Jing Wong/UC Berkeley)
2. Scanning electron microscope image of the single device capable of lasing and anti-lasing...

A short laser pulse can ionize a helium atom and change the quantum state of the remaining electron.

When a quantum system changes its state, this is called a quantum jump. Usually, these quantum jumps are considered to be instantaneous. Now, new methods for high-precision measurements allow us to study the time evolution of these quantum jumps. On a time scale of attoseconds, there time structure becomes visible. It is he most accurate time measurement of quantum jumps to date. Quantum particles can change their state very quickly, ie “quantum jump”. An atom, for example, can absorb a photon, thereby changing into a state of higher energy. With new methods, developed at TU Wien (Vienna), it is now possible to study the time structure of such extremely fast state changes...

A scanning tunneling microscope image shows two three-wheeled nanoroadsters created at Rice University and tested at the University of Graz. The light-activated roadsters, next to their molecular models, reached a top speed of 23 nanometers per hour. Credit: Alex Saywell/Leonhard Grill

Scientists are driving 3-wheeled, single-molecule “nanoroadsters” with light and, for the first time, seeing how they move. The Rice lab of nanocar inventor and chemist James Tour synthesized light-driven nanocars 6 years ago, but with the aid of experimental physicists in Austria, they’re now able to drive fleets of single-molecule vehicles at once...