The quantum yield [20,21] is an intrinsic property of a fluorophore
and is important for the characterization of novel fluorescent probes.
The quantum yield can be described by the relative rates of radiative
and non-radiative relaxation pathways which deactivate the excited
state. In other words quantum yield gives the probability of excited
state being deactivated by fluorescence rather than by another non radiative
mechanism [20]. An energetically excited state is formed when
a fluorophore absorbs a photon of light. The fate of this species is varied,
depending upon the exact nature of the fluorophore and its surroundings
and end result is deactivation and return to the ground state by
fluorescence, internal conversion and vibrational relaxation [21]