Publication Type:

Journal Article


Research on Chemical Intermediates, Volume 29, Number 3, p.293–305 (2003)



Photophysical properties of hemicyanine dyes (1 - 3) were investigated in solvents of varying polarity and viscosity. Hemicyanines possess relatively low fluorescence quantum yields (≤1{%}) in polar solvents. A significant increase in fluorescence quantum yield and lifetimes was observed with increase in viscosity of the solvent medium. The radiative, as well as nonradiative decay channels from the singlet-excited state were investigated by varying the viscosity of the medium. The viscosity-dependent radiationless relaxation observed in hemicyanine dyes is suggestive of a restricted rotor motion in the singlet excited state.

Cite this Research Publication

Dr. Zeena S. Pillai, P. K. Sudeep, and K. George Thomas, “Effect of viscosity on the singlet-excited state dynamics of some hemicyanine dyes”, Research on Chemical Intermediates, vol. 29, pp. 293–305, 2003.