| abstract |
An ammonia-modified titanyl phthalocyanine for use in preparing charge generating layer of a photoreceptor is disclosed. The ammonia-modified titanyl phthalocyanine is obtained by a process comprising the following steps: (a) reacting titanium tetrachloride with halogen-containing naphthalene to obtain an unmodified titanyl phthalocyanine; (b) dispersing the unmodified titanyl phthalocyanine in an organic solvent; and (c) subjecting the unmodified titanyl phthalocyanine to an ammonia-induced complexation-mediated crystal transformation so as to obtain the ammonia-modified titanyl phthalocyanine. The ammonia-induced complexation-mediated crystal transformation step can be achieved by either bubbling ammonia gas through the titanyl phthalocyanine-containing organic solution or by adding an ammonia-saturated aqueous solution to the titanyl phthalocyanine-containing organic solution. The ammonia-modified titanyl phthalocyanine is characterized by having Bragg diffraction angles of 7.5, 9.3, 13.6, 14.3, 17.9, 24.0, 27.2, and 29.1 degrees, and vibrational absorption resonances at 1492 cm-1, 1416 cm-1, 1333 cm-1, 1120 cm-1, 1072 cm-1, 962 cm-1, 894 cm-1, 752 cm-1, and 731 cm-1. The photoreceptor shows excellent spectral sensitivity at wavelengths in the near-infrared range (750-825 nm), and excellent cyclic stability evidenced by the observed negligible changes in the dark development potential after prolonged exposure cycles. |