INHOMOGENEOUS SPECTRAL BROADENING IN PENTACENE DOPED PARATERPHENYL CRYSTALS AT HIGH-PRESSURE AND LOW-TEMPERATURE

The effect of pentacene impurity concentration and non-hydrostatic hig h pressure (0-15 kbar) on the low temperature (15 K) absorption and em ission spectrum of pentacene in p-terphenyl is reported. The broad pen tacene band observed in monoclinic p-terphenyl suggests a frozen distr ibution of molecular twist angles in the low temperature monoclinic ph ase. Techniques are also presented for characterizing and minimizing i nhomogeneous spectral broadening of pentacene doped p-terphenyl crysta ls at high pressure.