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● Nano-Structured Solar Cell Materials

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Project 1: Engineering Electron-Phonon Coupling in Quantum Dot Solar Cells

(Sponsor: National Science Foundation)

High-energy photons (with energy exceeding the bandgap of a semiconductor) from the solar radiation create hot electrons, which are at an effective temperature much greater than that of the lattice. Through electron-phonon scattering events these hot electrons will cool until reaching thermal equilibrium with the lattice. This is the thermalization loss, a major limiting factor in photovoltaic solar energy conversion. A quantum dot solar cell (QDSC) provides an opportunity to increase the conversion efficiency by reducing the thermalization loss, as shown in the figure. The electron-phonon coupling factor will be predicted using first principle calculations and be measured using ultrafast femtosecond laser spectroscopy. The goal is to develop the criteria for the design of the optimized solar cells, which feature reduced electron-phonon coupling and enhanced cell efficiency.

Last updated 11/10/2007