Charge Transfer Complex Formation of Trinitrofluorenone with Polyvinylcarbazole and Ethylcarbazole

The molar absorption constants of the charge-transfer complexes of PVCz:TNF and of ethylcarbazole:TNF and the respective equilibrium constants for the formation of these complexes in a tetrahydrofuran solution have been determined by absorption measurements. Both materials exhibit two charge-transfer absorption bands. It is shown that these two bands correspond to two transitions of only one charge-transfer complex rather than to two complexes with different geometrical configurations of donor and acceptor molecules. For the PVCz:TNF complex the equilibrium constant is determined as K=0.5 l/mole, which is much smaller than the value K=3.05 l/mole found for the complex of ethylcarbazole and TNF.