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Spectroscopic Characterization of Multi-Exciton Generation Efficiency in Nano-Structured Materials


Kelly Gaffney, SLAC; Yi Cui and Mike McGehee, Materials Science & Engineering, Stanford University


This exploratory project aims at implementing a novel time-resolved spectroscopic diagnostic technique to validate recent experimental estimates of the efficiency of multiple exciton generation (MEG) in semiconductor nanoparticles following the absorption of a single high-energy photon. As opposed to traditional transient absorption measurements performed at the band gap energy, the proposed experiment uses the excited-state absorption as a signature of multiple exciton generation. This approach avoids using questionable assumptions, such as the weak interaction between multiple excitons within a quantum dot, in interpreting the results.

Progress Report



Gaffney, K. J., M. Ji, S. Park, S. T. Connor, Mokari, Y. Cui. “Efficient Multiple Exciton Generation Observed in Colloidal PbSe Quantum Dots with Temporally and Spectrally Resolved Intraband Excitation,” Poster presentation at Clusters, Nanocrystals, and Nanostructures Gordon Conference, 2009.