Photoconductivity Studies of Titanyl Phthaloc yanine

Recently, a new polymorph of TiOPc with characteristic XRD peaks at 2θ = 9.5 and 27.3° has been identified as having a quantum efficiency of carrier generation in the infrared approaching unity. In this paper, we will discuss the use of electric field induced fluorescence quenching technique in investigating the photoconductivity of this highly sensitive form of TiOPc. Linear correlation found between electric field induced fluorescence quenching and carrier generation in this material indicates that the photogeneration involves the field assisted dissociation of the first excited singlet state which is typical of other phthalocyanines. However, the highly sensitive TiOPc exhibits a smaller overall field dependence of carrier generation and an efficient carrier generation is “switched on” at much lower applied fields. Furthermore photoconductive and fluorescence responses are humidity dependent indicating that water plays an important role in the photogeneration processes.