Probing the excited state dynamics in perinone molecules for photovoltaic applications using transient absorption spectroscopy.

Nonfullerene polyaromatic molecules such as perinone are emerging as alternatives to fullerene derivatives due to their low manufacturing cost, ease of functionalization, and processing to improve the efficiency of optoelectronic devices. In this paper, we have used ultrafast transient absorption (TA) spectroscopy to probe the excited state dynamics in cis and trans perinone molecules. We have performed TA measurements in solution as well as thin films to provide a comprehensive understanding of excited-state processes occurring in cis and trans perinone molecules. Our results reveal the triplet state formation in perinone thin films through intersystem crossing and provide an in-depth understanding of the relaxation pathways of perinone molecules, which will be beneficial for designing and optimizing the device efficiencies of perinone based photovoltaic devices.