Mines solar cell research cited in Applied Physics Letters

GOLDEN, Colo., April 1, 2013 – Colorado School of Mines research focused on the quest for low-cost and highly efficient solar cells is featured on the cover of the April 1, 2013, issue of Applied Physics Letters, a publication of the American Institute of Physics.

“Highly Efficient Charge Transfer in Nanocrystalline Si;H Solar Cells,” was co-authored by researchers at Mines, Abengoa Solar, Inc., United Solar Ovonic LLC, MVSystems Inc., and the University of Denver.

Standard solar cells have efficiency limitations because electricity carriers excited by sunlight quickly lose some of their energy to heat. This energy loss can be prevented by collecting electricity carriers before they convert to heat through tiny “dots” of material.

The findings published in Applied Physics Letters indicates these dots provide a new paradigm for solar cells using crystalline silicon in hydrogenated amorphous silicon -- the electricity carriers are transported from the amorphous medium before they lose their energy to heat. This amorphous absorber allows for production of low-cost, hot carrier solar cells as the material is more easily created than crystalline materials.

Currently, most solar cells are made from crystalline silicon. These cells are efficient converters of sunlight into electricity, but they are fragile and heavy.

“The new paradigm presented in the Applied Physics Letter will open the way for light-weight thin-film solar cells which rival the efficiencies of the silicon cells that now dominate the market,” said Craig Taylor, one of the article’s authors and director of the Renewable Energy Materials Research Science and Engineering Center (REMRSEC) at Mines, where the research was conducted.

Taylor noted the concept “may not be surprising in hindsight,” but added the same is true of many important scientific discoveries.

The REMRSEC, funded by the National Science Foundation under a cooperative agreement through the MRSEC program, has had a major influence on Mines -- from initiating a new framework for hiring faculty to campus wide mentoring programs for students. The Mines center is the only one in the MRSEC program solely devoted to materials for renewable energy applications. It functions with active participation by many senior scientists from the National Renewable Energy Laboratory (NREL).

Mines and NREL researchers have taken these encouraging research results to the next level under a newly established photovoltaics program funded by the Department of Energy. Under this program, scientists will create prototype solar cells that confirm the predictions presented in the Applied Physics Letter. The close association with NREL scientists facilitates this rapid transition from basic understanding to the applied research and development stage, and eventually to the production of dramatically improved solar cells. 

"These results are highly significant for the photovoltaics community,” said John Poate, vice president of research and technology transfer at Mines. “I am pleasantly surprised at the speed with which the fundamental ideas have been transferred to a more applied project. This rapid transfer of basic understanding toward practical applications is necessary if we are going to increase the renewable energy component of our energy mix."


Karen Gilbert, Director of Public Relations, Colorado School of Mines / 303-273-3541 / KGilbert@mines.edu