[amor de cosmos]

New Solar Cell Is More Efficient, Less Costly
November 8, 2013

American innovators still have some cards to play when it comes to squeezing more efficiency and lower costs out of silicon, the workhorse of solar photovoltaic (PV) cells and modules worldwide.

A recent breakthrough — the product of a partnership between manufacturer TetraSun and the Energy Department's National Renewable Energy Laboratory (NREL) — could spark U.S. solar manufacturing when the approach hits the assembly line next year. The innovative design, simple architecture, and elegant process flow for fabricating the cells make the technology a prime candidate for large-scale production.

Solar industry leader First Solar acquired TetraSun in April 2013, about the time R&D Magazine honored TetraSun and NREL with one of its coveted R&D 100 Awards for the year's top innovations.

Potentially Disruptive Technology Attracted Attention of PV Incubator Program

Typically, silicon PV cell manufacturers add a grid of thin silver lines to the cell via a screen-printing process to form the front contacts.

The TetraSun cell instead loads 50-micron-wide copper electrodes on its front contacts in a way that prevents diffusion of the metal—which can degrade performance. The new process exceeds the performance of traditional heterojunction cells without the need of any special equipment, complicated module assembly, or costly transparent conductive oxides. That adds up to a significant cost advantage when it comes to high-volume manufacturing.

"It's a potentially disruptive technology, and that's why we decided to work with TetraSun," said NREL's Martha Symko-Davies, who headed the Energy Department's SunShot Initiative PV Incubator program when TetraSun received a grant from it back in 2010. "The Incubator program supports potentially disruptive innovations from small startups.

"This shows we still have innovation in the United States. People thought there was nothing left to be done in silicon, but there is something left to be done."

http://www.nrel.gov/news/features/fe...eature_id=4309