Effects of traps on triplet-triplet annihilation in phenanthrene crystals

Abstract

The temperature dependences of delayed and prompt fluorescence spectra for anthracene doped phenantherene crystals (2 x 10 −5 and less than 10 −6M/M) have been studied in the temperature range 77-293 K. The experimental results indicate that a shallow trap the depth of which is 250 cm −1 competes with the deep anthracene trap in triplet excitation energy transfer from the host. The concentration of the shallow trap is estimated to be ca 2.5 x 10 −3 M/M.