Optical Hyperdoping: Transforming Semiconductor Band Structure for Solar Energy Harvesting

Harvesting solar energy at the terawatt scale requires technologies that can be produced inexpensively using Earth-abundant materials. Although technologies built from Earth-abundant materials exist for converting solar energy to electrical energy or chemical energy, none are yet cost-competitive with fossil fuels. Meeting the challenge of harvesting solar energy with Earth-abundant materials such as Si and TiO2 will require transformative approaches to increase efficiency, lower manufacturing cost, and reduce material requirements. While these materials have been widely studied, we bring a totally new multidisciplinary approach to transforming the band structure of semiconductors.

We propose developing techniques for engineering the band structure of semiconductors, thus, altering their optical properties so as to transform them into dramatically more efficient solar energy converters. We will engineer the band structure by optical hyperdoping via femtosecond laser irradiation that leads to higher levels of doping than are possible using other methods. To better understand and optimize the dynamics of optical hyperdoping, we will develop new mathematical tools for modeling the hyperdoping process, focusing on the quantum mechanics associated with the unusual band structure, as well as methods for understanding and controlling the non-equilibrium process itself. The multidisciplinary team of PIs will integrate expertise in mathematics and continuum modeling of optical hyperdoping (Michael Brenner), theoretical chemistry and modeling at the quantum level (Alán Aspuru-Guzik), materials science of optoelectronic materials (Eric Mazur), and chemistry of surfaces and interfaces (Cynthia Friend) to make a concerted attack on creating and understanding new materials with transformative potential and broad impact.