In this work we apply a combination of steady state and time resolved luminescence and absorption spectroscopies to investigate the excited-state dynamics of a recently developed molecular photoswitch, belonging to the hydrazone family. The outstanding properties of this molecule, involving fluorescence toggling, bistability, high isomerization quantum yield and non-negligible two-photon absorption cross section, make it very promising for numerous applications. Here we show that the light induced Z/E isomerization occurs on a fast <1 ps timescale in both toluene and acetonitrile, while the excited state lifetime decreases with increasing solvent polarity, suggesting a partial charge transfer nature of its low lying excited state. Time resolved luminescence measurements evidence the presence of a main emission component in the 500-520 nm spectral range, attributed to the Z isomer, and a very short living blue-shifted emission, attributed to the E isomer. Finally, transient absorption measurements performed upon far-red excitation are employed as an alternative method to determine the two-photon absorption cross-section of the molecule.
Keywords: Hydrazone, pump-probe spectroscopy, time resolved fluorescence
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Iagatti, A.; Shao, B.; Credi, A.; Ventura, B.; Aprahamian, I.; Di Donato, M. Beilstein Arch. 2019, 201948. doi:10.3762/bxiv.2019.48.v1
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