Figure 4.

(a) Complex frequency-dependent conductivity measured at 0.5 ps, at the peak of the photoconductivity by 3.1 eV pump. The conductivity is scaled to the density N of absorbed photons; the solid line represents the Drude–Smith fitting described in the SI. (b) Complex frequency-dependent conductivity comparison between the one measured at 10 ps after photoexcitation with 3.1 eV pump (red), and that at the peak of the imaginary conductivity with 1.63 eV pump (blue, rescale with a factor of 1.35 for comparison). The data are fitted by a Lorenztian model described in the main text. Two fitting examples are given here with the center frequency for the black one 25 THz and that for the gray one 6 THz. (c) Tracking of exciton formation and recombination dynamics in GNRs, inferred from the fitting described in the main text. The red solid line is a fitting combining an exponential ingrowth and a following decay, from which the exciton formation and decay time are obtained.