Two-dimensional white-light spectroscopy

Two-dimensional white-light spectroscopy (2D-WL spectroscopy) is a powerful tool we have developed to unravel electronic couplings and energy or charge transfer in systems of interest for solar energy. By using a white light continuum for both pump and probe, we map the correlations between electronic states that span almost the entire solar spectrum.

                                   

Figure 1. (Left) 2D-WL spectra of a carbon nanotubes thin film at waiting time T = 2500 fs. (Right) Comparison of our pump spectrum to the solar spectrum.

Although the white light continuum has a low fluence, electronic transitions have large absorption cross sections, allowing us to measure the nonlinear signal. We have measured 2D-WL spectra on several systems of interest in solar energy applications including quantum dots, pentacene films, and carbon nanotube thin films.

                        

Figure 2. 2D-WL spectra of (left) PbSe quantum dots and (right) pentacene films.