Wire Power
This 300-nanometer-wide silicon wire (left) generates electricity from sunlight. Such nanowire solar cells would initially be useful in tiny sensors, or in robots whose electronics might need built-in power. But arrays of microscopic wires could change the economics of solar power by enabling solar cells built from cheap materials such as low-grade silicon or even iron oxide–rust.
A number of such cheap materials absorb light and generate electrons, but defects in the materials usually “trap” the electrons before they can be collected. Microscopic wires, though, can be made thin enough to allow electrons to slip out easily and generate current, even if the material has defects. And the wires can be long enough to absorb plenty of photons from sunlight hitting them at an angle.
The image is colored to highlight functional layers of the nanowire, which was made in the lab of Harvard University chemist Charles Lieber. The layers are made of silicon modified in ways that give them properties useful for generating and harvesting charged particles. To make solar panels, the microscopic wires could be grown in dense arrays. The below image shows a cross section of a silicon-wire array fabricated in the labs of chemist Nathan Lewis and physicist Harry Atwater at Caltech. Each wire is two or three micrometers in diameter. Both groups are in the early research stages, but arranging microscopic wires in a forestlike configuration could lead to new materials that harvest sunlight cheaply and efficiently.
Courtesy of Brendan Kayes and Michael Filler
Keep Reading
Most Popular
Large language models can do jaw-dropping things. But nobody knows exactly why.
And that's a problem. Figuring it out is one of the biggest scientific puzzles of our time and a crucial step towards controlling more powerful future models.
OpenAI teases an amazing new generative video model called Sora
The firm is sharing Sora with a small group of safety testers but the rest of us will have to wait to learn more.
Google’s Gemini is now in everything. Here’s how you can try it out.
Gmail, Docs, and more will now come with Gemini baked in. But Europeans will have to wait before they can download the app.
This baby with a head camera helped teach an AI how kids learn language
A neural network trained on the experiences of a single young child managed to learn one of the core components of language: how to match words to the objects they represent.
Stay connected
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.