Electric-field-induced broadening of spectral holes in zinc phthalocyanine

The influence of an externally applied electric field on spectral holes bur nt into the Q band of zinc phthalocyanine doped into poly(vinyl-butyral) ha s been investigated. The changes in hole shape, as a function of electric f ield, have been monitored and a linear Stark effect has been observed. The broadening can be analysed as having contributions from in-plane distortion s of the chromophore that remove its nominal four-fold symmetry and thus th e degeneracy of the Q band. Other contributions, perhaps associated with ax ial ligation of the chromophore, remove the plane of symmetry and contribut e differently to the broadened profile. (C) 1999 Elsevier Science B.V. All rights reserved.