Oil major BP and the California Institute of Technology (Caltech) have announced a solar research programme to explore a concept based on growing silicon by creating arrays of nanorods rather than by the conventional method of casting ingots and cutting wafers.

The nanorod technique, in which the small cylinders of silicon would be tightly packed in an array, will be able to efficiently absorb light along the length of the rods and may make the cost of solar electricity more competitive.

The multi-million dollar five-year research programme will be directed by two prominent chemicals scientists at Caltech, Dr Nate Lewis and Dr Harry Atwater. Lewis’ group will investigate uses of nanotechnology to create solar cell materials from nanorods and nanowires. Atwater’s group will investigate approaches to create silicon-based single junction and compound semiconductor multijunction nanorod solar cells, using vapor deposition synthesis methods that are scaleable to very large areas. Says Atwater: “Using nanorods as the active elements opens up very new approaches to design and low-cost fabrication of high performance solar cells.”

Lee Edwards, president of BP Solar, commented: “Nanorod technology offers enormous promise, however, like any new technology, challenges remain to make it commercially viable at scale.”