BP Solar Teams with Caltech to Explore Solar Technology Production

June 28, 2006 by Jeff Shepard

BP Solar and the California Institute of Technology have teamed up in a multi-million dollar research program that could open the door to a radical new way of producing solar cells, making the cost of solar electricity more competitive and increasing current efficiency levels.

The program was announced at the Photovoltaics Summit 2006 in San Diego. For an initial five year period, BP and Caltech will explore a concept based on growing silicon by creating arrays of nanorods rather than by casting ingots and cutting wafers, which is the current conventional way of producing solar cells. Nanorods are small cylinders of silicon that can be 100 times smaller than a human hair and would be tightly packed in an array like bristles in a brush.

A solar cell based on an array of nanorods will be able to efficiently absorb light along the length of the rods by collecting the electricity generated by sunlight more efficiently than a conventional solar cell. The contract has clear links with BP's long term technology strategy and builds on its proven strategy of partnering with some of the world's leading universities on key technology challenges. Caltech is one of many prestigious universities BP is working with globally on key technology projects. The program is also aligned with the launch of BP Alternative Energy in November 2005 - a new business focused on developing low carbon options for the power industry which also includes the BP Solar business.

The Caltech solar nanorod program will be directed by two prominent scientists at Caltech, Dr. Nate Lewis and Dr. Harry Atwater. Dr. Lewis is the George L. Argyros Professor of Chemistry and is an expert in the areas of surface chemistry and photochemistry. Dr. Atwater is the Howard Hughes Professor and Professor of Applied Physics and Materials Science and is an expert in electronic and optoelectronic materials and devices. In addition, eight postdoctoral researchers and graduate students will work on the program.

Lewis' group will investigate uses of nanotechnology to create designer solar cell materials, from nanorods to nanowires, in order to change the conventional paradigm for solar cell materials. "Nanotechnology can offer new and unique ways to make solar cell materials that are cheaper yet could perform nearly as well as conventional materials," said Dr. Lewis.

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. According to Dr. Atwater, "Using nanorods as the active elements opens up very new approaches to design and low-cost fabrication of high performance solar cells."