Spectrophysics of Coumarin-Based Chromophore

Abstract

In this work, we comprehensively explore the spectral and photophysical properties of a coumarin-based dye (1) in neat solvents. The modulation of stokes shifts, emission quantum yields (ФF) and excited-state lifetimes of 1by local environment (polarity, polarizability, viscosity and hydrogen bonding) signifies the formation of intramolecular charge state (ICT) from the amino group to the coumarin moiety. Collectively, in the more viscous polar solvents the rotation of the amino group is restricted, exponentially decreasing the non-radiative rate constants (knr). Keywords :#SPECTROPHYSICS #INTERMOLECULAR_CHARGE_TRANSFER #NON-RADIATIVE_RATE_CONSTANT #EXCITED-STATE_LIFETIME #LOCAL_ENVIRONMENT.