Fig. 3: Triplet-like PIA and photoinduced thermal artifacts in film 1.
From: Parallel triplet formation pathways in a singlet fission material
a TA spectra of film 1 after photoexcitation at 2.3 eV from 0.2 ps to 1 ns with 1.75 μJ/cm2. Steady-state absorption (gray solid line) and PL (gray dashed line) are presented in (a) for reference. TA spectra near 2.3 eV are truncated due to pump scattering. b equivalent to (a) but divided into three time regimes to highlight isosbestic points (gray vertical dashed lines) involved in each step of the spectral evolution. The bottom panel is taken from excitation with 53.1 μJ/cm2 to show the presence of the same isosbestic point as in the 1.75 μJ/cm2 data. c TA spectra in the range of 1000–7000 ps with the pump fluence of 53.1 μJ/cm2. The first derivative of the steady-state absorption spectrum (black solid line), which is shifted in parallel, is also shown for comparison. d Low- (1.75 μJ/cm2 for 2.3 eV pump and 3.5 μJ/cm2 for 1.84 eV) and high-pump-fluence (53.1 μJ/cm2, 2.3 eV pump) TA kinetics averaged in the range of 1.5–1.35 eV. The black lines are the best global fits of the 2.3 eV pump kinetics with a multiexponential function.
