Femtosecond stimulated Raman spectroscopy – guided library mining leads to efficient singlet fission in rubrene derivatives† † Electronic supplementary information (ESI) available: Detailed experimental procedures, absorption spectra of crystals, actinic pulse profile, raw FSR data of crystalline rubrene, FM-rubrene and F-rubrene, ground state addition kinetics, transient absorption data, FSR of crystalline FM-rubrene with grating filter, transient absorption of FM-rubrene solution, coordinates of optimized singlet and triplet state geometries. See DOI: 10.1039/d1sc04251c

ABSTRACT: Chromophores undergoing singlet fission are promising candidates for harnessing solar energy as they can generate a pair of charge carriers by the absorption of one photon. However, photovoltaic devices employing singlet fission are still lacking practical applications due to the limitations within the existing molecules undergoing singlet fission. Chemical modifications to acenes can lead to efficient singlet fission devices, but the influence of changes to molecular structure on the rate of singlet fission is challenging to model and predict. Using femtosecond stimulated Raman spectroscopy we have previously demonstrated that the triplet separation process during singlet fission in crystalline rubrene is associated with the loss of electron density from its tetracene core. Based on this knowledge, we mined a library of new rubrene derivatives with electron withdrawing substituents that prime the molecules for efficient singlet fission, without impacting their crystal packing. Our rationally chosen crystalline chromophores exhibit significantly improved singlet fission rates. This study demonstrates the utility and strength of a structurally sensitive spectroscopic technique in providing insights to spectroscopy-guided materials selection and design guidelines that go beyond energy arguments to design new singlet fission-capable chromophores. In the race to find efficient singlet fission materials, picking a winner is not easy. Femtosecond stimulated Raman spectroscopy can help us choose the best candidates, as demonstrated here in choosing from a library of rubrene derivatives.

SUBMITTER: Bera K 

PROVIDER: S-EPMC8549787 | biostudies-literature |

REPOSITORIES: biostudies-literature