Figure 5.
(a–d) Variations of the (a, b) S11 and (c, d) S33 transient absorption change (ΔOD) against pump–probe delay and probe energy for (a, c) HgTe-filled and (b, d) unfilled semiconducting SWCNTs in solution. The horizontal lines in panels (c) and (d) mark the energies of the different photobleaching (PB) and photoabsorption (PA) features. The pump photon energy and fluence were 1.98 eV (625 nm) and 1.1 mJ/cm–2 per pulse, respectively. (e, f) Normalized TA kinetics at different energies, (e) in the S11 spectral region and (f) in the S22 and S33 regions. Fits (purple for the unfilled and magenta for the HgTe-filled) are as described in the text based on the bimolecular rate equation model in eq 3). This model did not reproduce the dynamics of the PA feature at around 3.09 eV. (g) Energy diagram of (6,5) and possible exciton relaxation pathways, under the influence of HgTe NW filling, which reduced the S33 and S11 Auger rates and thus enhanced its fluorescence. The upward red arrow denotes the pump.