Organic photoconductors with C-60 for xerography

Our aim is to improve the charge-generation efficiency of organic-photorece pror materials used in xerography and for laser printers by mixing the mate rial with buckminsterfullerene C-60. The improvement is based on an electro n transfer from the excited excitonic state of the photoreceptor molecule t o the C-60 thus reducing the recombination probability. Typical materials s tudied are various metal-phthalocyanines (M-Pc, with M=TiO, VO, Ni, Fe, Cu) and metal-free H-2-Pc. Using techniques like X-ray absorption near edge sp ectroscopy (XANES) and photoelectron spectroscopy with ultraviolet radiatio n (UPS) we demonstrate that the electron transfer is energetically possible and no ground state electron transfer occurs. The observation of fluoresce nce quenching upon doping with C-60 validates the electron transfer-model. (C) 1999 Elsevier Science Ltd. All rights reserved.