Ultrafast photoexcitations in para-hexaphenyl

The photoexcitations in the visible and near infrared spectral region of textured polycrystalline para-hexaphenyl (PHP) films are investigated by ultrafast pump-probe spectroscopy. We observe a strong stimulated emission band at 2.7 eV and photoinduced absorption bands. We assign this features to singlet exciton, triplet exciton, and polaron absorption, using field assisted pump-probe measurements.