About some properties of the poly(N-vinylcarbazole) doped with a halogen (I, Cl, Br)

After doping with a halogen (X = I, Br or Cl) of the PVK, there is charge t ransfer (CT) complex formation as shown by electron spin resonance (ESR), o ptical absorption and X-ray electron spectroscopy (XPS). The conductivity o f this CT-complex depends on halogen. For halogen with higher electronegati vity (Br, Cl) there is not only CT-complex formation, but there is also som e polymer degradation by the halogen. This degradation is amplified when th e temperature during doping is increased. It results in the formation of a new amorphous polymer; with some crystallites of carbazole and NH4X embedde d in an amorphous polymeric matrix. The increase of the conductivity of the se new polymers is probably related to the formation of some pi bonds. It a ppears that, after all, doping with iodine is more promising since there is some polymer degradation even at room temperature with other halogens. (C) 1998 Elsevier Science Ltd. All rights reserved.