Photophysics of Benzoxazole and Dicyano Functionalised Diketopyrrolopyrrole Derivatives: Insights into Ultrafast Processes and the Triplet State

In this study, we used femtosecond pump-probe spectroscopy to investigate the photo-initiated dynamics of thiophene linked DPP derivatives. The thio-DPPs are further functionalised by different electrons withdrawing terminal groups, namely benzoxazole and thiophene dicyanide. The benzoxazole derivative is strongly emissive and directly relaxes directly to the ground state chloroform solution. Thiophene dicyanide derivative exhibits distinct spectral evolution in the first 10 ps, associated with structural and vibronic process. Later, it crosses over to the triplet state with a yield of 20%. In the solid-state thin film, we observed a signal that resembles singlet fission. However, upon careful analysis of temperature-dependent steady state absorbance spectra, we conclude that these features are due to laser-induced thermal artifacts. We describe a simplified excited state evolution in the thin film that does not include any additional excited states. These findings have significant implications for the analysis of triplet formation, which plays a major role in the photophysics of many organic materials.PMID:38572936 | DOI:10.1002/cphc.202300872

Source: Chemphyschem - April 4, 2024 Category: Chemistry Authors: Yadu Ram Panthi Muhammed Arshad Thottappali Petra Hor áková Lubom ír Kubáč Ji ří Pfleger Miroslav Men šík Tuhin Khan Source Type: research