Figure 1

(a) The XRD pattern of a RR-PTV film showing the prominent out-of-plane [100] band and its harmonics, as well as an in-plane [010] band that shows lamellae formation;[19] the red line drawn on the various bands is a Gaussian fit; the fourth peak is a sum of two Gaussians with different widths. The inset shows the backbone structure of the RR-PTV polymer. (b) The PL and absorption spectra of RR-PTV in dilute solution. The line through the data points is a fit using a modified Franck-Condon model (see text). (c) Same as in (b) but for RR-PTV film. Various vibronic transitions were labeled for clarity. (d) The EA spectra of RRa-PTV (dashed red line) and RR-PTV (full black line). The spectral EA features related to 1${}^1$B${}_{\mathrm{u}}$ and m${}^1$A${}_{\mathrm{g}}$ are assigned. The inset is a blow-up of the EA spectrum from 2.4 to 3.0 eV that includes the $\mathrm{m}{}^1{\mathrm{A}}_{\mathrm{g}}$ state.Reuse & Permissions

Figure 2

The transient PM spectrum of RR-PTV film measured at various delay times, $t$, in (a) mid-infrared spectral range and (b) visible/near-infrared spectral range; PA${}_1$ and PA${}_2$ bands are assigned. The inset to (a) is a schematic of the PTV essential states and associated optical transitions. (c) and (d) The respective decay dynamics of PA${}_1$ at 0.95 eV and PA${}_2$ at 1.6 eV. The insets to (c) and (d) focus on the PA formation and decay evolution near t $=$ 0, where the data (red solid circles) are fitted with an exponential formation and decay processes (green line), taking into account the pump/probe cross-correlation function (black line).[16]Reuse & Permissions

Figure 3

(a) and (b) The transient PM response at $\hslash \omega$(probe) $=$ 1.80 eV of two RR-PTV films with different thicknesses: (a) $d$ ≈ 60 nm, and (b) $d$ ≈ 330 nm. The ultrafast electronic response (PB) and the transient strain (TS) response that show an oscillatory component are assigned. Note that the oscillation period, τ${}_{\mathrm{T}}$, is different in (a) and (b). The inset to (a) shows in more detail the PB decay and TS onset response for $d$ ≈ 60 nm; the inset in (b) shows Δ$T$($t$) parallel ($\parallel$) and perpendicular (⊥) response dynamics and the resulting polarization degree, P($t$), for a film of $d$ ≈ 210 nm. (c) The PM spectra of RR-PTV film of $d$ ≈ 60 nm in the $\hslash \omega$(probe) interval 1.6–2.6 eV, which show the evolution of the PB response. The inset compares the PB spectrum at 60 ps (dominated by the TS response) with the spectrum of the absorption derivative, $d$α(ω)/$d$ω.Reuse & Permissions