ABSORPTION-COEFFICIENTS AND FLUORESCENCE QUANTUM YIELDS OF PORPHYRIN FILMS DETERMINED BY OPTICAL AND PHOTOACOUSTIC SPECTROSCOPIES

The optical properties (absorption coefficients, refractive indices) and the fluorescence quantum yields of solid films of tetraphenylporphins of hydrogen, magnesium and zinc were determined, using optical absorption and photoacoustic spectroscopy. Absorption spectra show clear differences relative to spectra in fluid solution. Fluorescence quantum yields reveal the influence of central atom substitution and are in all cases much lower than the yields in solution, supporting evidence of appreciable aggregation of the porphyrins in the solid phase. The optical and luminescent parameters are independent of sample thickness in the range between 0.2 and 1.0-mu-m.