Synopsis: Band together

Semiconductor alloys offer one way to improve the efficiency of solar cells.

The sun offers us light for free, but most of the spectrum is missed by semiconductor solar cells, which are typically only efficient at converting light to electricity over a window of wavelengths. Connecting a series of different semiconductors can capture more of the solar spectrum, but these devices are complex and expensive to fabricate.

Now, in a paper appearing in Physical Review Letters, Nair López Martínez and colleagues at Lawrence Berkeley National Laboratory and RoseStreet Labs Energy, both in the US, present a prototype solar cell where they fold the light sensitivity of many semiconductors into a single material.

A semiconductor will absorb light most efficiently at the energy of its band gap—the energy it takes to excite an electron from the valence to the conduction band. To get around the limitation of a single band gap, López et al. engineered a semiconductor alloy, GaNAs, which has both an intermediate and wide band gap and is therefore sensitive to both low- and high-energy light. In their test of the first “proof of concept” solar cell based on an intermediate band semiconductor, the team shows their device has a promising efficiency over a wide spectrum of the sun’s light. – Jessica Thomas


More Announcements »

Subject Areas

Semiconductor PhysicsMaterials ScienceEnergy Research

Previous Synopsis


Making waves

Read More »

Next Synopsis

Related Articles

Synopsis: Valley of the Dichalcogenides
Semiconductor Physics

Synopsis: Valley of the Dichalcogenides

A magnetic field can be used to change the “valley” states that emerge in certain semiconductors. Read More »

Viewpoint: Relaxons Heat Up Thermal Transport
Materials Science

Viewpoint: Relaxons Heat Up Thermal Transport

A recasting of the theory that underlies thermal transport in electrical insulators relies on new vibrational modes called relaxons. Read More »

Viewpoint: Improving Electronic Structure Calculations
Materials Science

Viewpoint: Improving Electronic Structure Calculations

A new approach to calculating the properties of molecules and solids may offer higher accuracy at reasonable computational cost, accelerating the discovery of useful materials. Read More »

More Articles