A new photovoltaic material works and that is in the best solar cells, but promises to be much cheaper. The material, created by researchers at Caltech, is a flexible array of light absorption of silicon microwire and reflect light metal nanoparticles embedded in a polymer.

Computer models suggest that the material could be used to produce solar cells that convert 15 to 20 percent of solar energy into electricity – at par with existing cells of high-performance silicon. However, the issue should be only 1 percent of the materials used today, which could lead to a drastic reduction of costs. The researchers were led by Harry Atwater, professor of applied physics and materials science at Caltech.

The key to the performance of the new material is its ability to trap light. More than one photon bounces within the active part of a solar cell, the greater the possibility of releasing an electron.All cells of high efficiency solar have anti-reflective coatings to the light trap for help. However, these cells requires more use of silicon and is to be cut from wafers, a product of the process.

“The promise of light trapping has always been that you could use less silicon and reduce costs, but it was difficult to implement,” says Eli Yablanovitch, professor of electrical engineering at the University of California, Berkeley, who was not involved in the investigation .

Many groups have used structures such as nanowires and microwires in an effort to resolve this problem. Photovoltaic Caltech group, which uses silicon microwires, a new level of performance in large part due to the addition of nanoparticles of reflection.

Atwater group grew arrays of silicon microwire of a gas on the surface of a reusable model. The model determines how they are dense forests grow, and the diameter of each wire. The tables are set low, and without further processing, making a poor solar material. But the son is treated with an anti-reflective coating and a polymer-coated rubber mixed with aluminum oxide nanoparticles highly reflective. Once the sets of polymer, the whole can be peeled like a sticker.Over 90 percent of the resulting material is composed of polymers at low prices, and the model can be used again and again.

“These materials are flexible, but they have the properties of a silicon wafer,” said Atwater.When light hits the solar carpet composite, bounces around, reflecting on the alumina particles until it can be absorbed by a Microwire.