Characterization of the ultrafast spectral diffusion and vibronic coherence of TIPS-pentacene using 2D electronic spectroscopy

TIPS-pentacene is a small-molecule organic semiconductor that widely used in optoelectronic devices. It has been studied intensely owing to its ability undergo singlet fission. In this study, we aim develop further understanding of the coupling between electronic and nuclear degrees freedom (TIPS-Pn). We measured analyzed 2D spectra TIPS-Pn solutions. Using center line slope (CLS) analysis, characterized frequency-fluctuation correlation function 0–0 vibronic transition. Strong oscillations CLS values were observed for up 5 ps with frequency 264 cm?1, which are attributable large ring-breathing vibrational mode. addition, detailed analysis allowed us retrieve two spectral diffusion lifetimes, attributed inertial diffusive dynamics solvent molecules. Amplitude beating also uncovered couplings another mode at 1173 cm?1. The experimental results can be described using displaced harmonic oscillator model. By comparing simulated data values, estimated Huang–Rhys factor 0.1 demonstrated how useful method characterizing strength coupling.