Femtosecond laser doping of silicon; a novel fabrication method for photovoltaics

Harvard University, Cambridge MA

Investigators

Abstract

CBET-0754227 Mazur Silicon is a desirable material for solar cells because of its abundance, non-toxicity, and existing manufacturing infrastructure; however, the high costs of producing silicon solar cells have prevented them from taking a larger role in the electricity generation market. Many proposals exist for achieving higher efficiencies in solar cells, as well as proposals for how to manufacture them less expensively. Oftentimes, however, these goals are mutually exclusive. The research we propose using short, intense pulses of light to modify silicon and fabricate solar cells could achieve both lower costs and higher efficiencies simultaneously. Additionally, our research will make it possible to achieve these goals using silicon, an abundant material for which our society has tremendous engineering expertise (due to its ubiquitous use in electronics such as computers). As such, this research will help our country transition from fueling our energy needs via the carbon intensive combustion of fossil fuels to a renewable and sustainable future. Intellectual Merit: Prof. Eric Mazur's research group has developed a novel technique for constructing solar cells using very short pulses of laser light. Using these ultra-short laser pulses, we can endow silicon with remarkable optical properties, such as strong sensitivity to infrared colors of light that pass through a standard silicon solar cell without being absorbed. The focus of this research project is to leverage the group's expertise with lasers and solid-state materials to characterize this exciting new type of silicon and determine its promise as a new material in solar cells. During this project, a number of prototype silicon solar cells will be fabricated, including thin-film, multijunction, and nanoparticle-enhanced solar cells. These devices will represent the fruit of a novel fabrication technique that will lower costs and raise efficiencies for silicon-based solar cells. Our group has a well-proven record of scientific discovery and innovation, as evidenced by highly cited publications in peer reviewed journals, patents granted, and the launch of a rapidly growing start-up company based on technology discovered by the group. Broader Impact: While our work will directly advance the state of solar cell technology, the proposed work will contribute to a better understanding of the exotic materials that are produced in the intense conditions of ultrashort laser pulses. Additionally, our work will contribute to the education and training of future multidisciplinary scientists and engineers through research-based education of undergraduate and graduate students. Through our work with local high schools, NSF sponsored programs, and the high representation of women in our research group, we will broaden participation of underrepresented groups. Our extensive collaborations with academic and industrial partners around the world will enhance infrastructure for research, as will our participation in NSF-funded multi-user facilities. Finally, using the group's well-established program for integrating outreach and public education with research, this work will be broadly disseminated to the general public.