2D electronic spectroscopy study of TIPS - pentacene

Abstract

The molecule TIPS – Pentacene has gained a lot of attraction recently due to its ability to exhibit the singlet fission phenomenon, which has the potential of improving power conversion efficiency significantly in photovoltaic devices 1 . Therefore, investigating into the photophysical properties of this molecule can assist researchers in better understanding the singlet fission phenomenon. 2D Electronic spectroscopy of TIPS – Pentacene in solution shown a strong beating at 265cm -1 in both the amplitude and the central line slope 2 , which corresponds to a breathing mode of the molecule. The 2D spectra , , can be understood using the theory of a two level system coupled to a series of harmonic oscillators 3 . The resultant lineshape function 𝑔(cid:4666)𝑡(cid:4667) of the system can be partitioned into two functions: 𝑔 (cid:3029) (cid:4666)𝑡(cid:4667) (environment) and 𝑔 (vibrational mode). A full expansion of the lineshape function 𝑔(cid:4666)𝑡(cid:4667) in the third order nonlinear optical response functions can be used to simulate the experimental 2D spectra, including the 2D Fourier map at 265 cm (cid:2879)(cid:2869) (Fig.1c) and the Centre Line Slope analysis (Fig.1d).