Effect of Solvent Polarity on the Quantum Yield of Acriflavine Molecule

Abstract

The absorption and fluorescence spectra have been studied and measured for Acriflavine (AF) solution which dissolved in polar solvents as a function of concentration and solvent at excitation wavelength (λex= 414nm) . The quantum yield (Фfm ) , the Radiative fluorescence lifetime (τFM ) , rate parameter of Radiative (KFM) and non-Radiative processes (KIM) are be calculated . Where the quantum yield be found equal to (Фfm =0.84) and ( Фfm = 0.83) for Acriflavine (AF) solution dissolved in N-N-dimethyl formamide (Dmf) and dimethyl sulphoxide (DMSO)at concentration (1x10-5M ) , respectively. But the quantum yield of Acriflavine (AF) in water is equal to ( Фfm = 0.81) at same concentration . This different in the values of quantum yield refers to the effect of polarity and to the intermolecular charge transfer phenomena (ICT) between the amine group and the aromatic ring , since when the polarity of solvent increasing leads to decreasing in the intensity of the fluorescence spectra , also a shift of fluorescence spectrum occurs towards the longer wavelength (redshift) , and this lead to decrease the quantum yield value . The quantum yield measurement was calculated relative to standard compound of Rhodamine B with quantum efficiency (qFM = 0.97) at same excitation waveleng