Red shift in fluorescence of naphthalene doped by anthracene and perylene

Abstract

The fluorescence in naphthalene is investigated systematically by doping it with different amounts of anthracene and perylene with a view to obtain luminophors emitting at longer wavelengths. The fluorescence spectra of naphthalene luminophors are recorded on recording spectrofluorophotometer. It is observed that the addition of small amount of anthracene completely quenches the weak violet fluorescence of naphthalene and new anthracene like emission band appears in the fluorescence spectra of doped naphthalene. The intensity of anthracene like emission band is maximum at 10−2mol anthracene per mole naphthalene. The addition of perylene as another impurity not only quenches the anthracene like emission but also acts as wavelength shifter. Thus, the fluorescence spectra of naphthalene containing anthracene and perylene shows anthracene like emission followed by a broad tail towards red. The anthracene like emission is explained on the basis of fluorescence sensitization while red side of the spectrum is attributed to emission arising from charge transfer complex formed in the excited state.