Solution-state photophysics of N-carbazolyl benzoate esters: dual emission and order of states in twisted push–pull chromophores?

Physical Chemistry Chemical Physics Pub Date: 2016-09-06 DOI: 10.1039/C6CP04619C

Abstract

The stepwise photoinduced charge transfer in a series of N-carbazolyl benzoate ester push–pull chromophores has been studied in solution. Dual emission from the locally excited (LE, the lowest-energy singlet excited state of 1Lb nature localized on the carbazole donor) and the highly polarized, intramolecular charge-transfer states of (pre)-twisted type (TICT states) is observed in non-polar and polar solvents. Ultrafast transient spectroscopy reveals that the excitation into the 1Lb LE state is followed by rapid (～ps) charge separation into an emissive TICT state. Excitation into the second singlet excited state localized on the carbazole (S2) with 1La nature results in sub-100 fs population of both 1Lb and TICT states.

Graphical abstract: Solution-state photophysics of N-carbazolyl benzoate esters: dual emission and order of states in twisted push–pull chromophores
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