チオピロロピロールの固体スペクトルと光ディスクへの応用 Solid-State Spectra of Dithioketopyrrolopyrrole and their Application to Optical Disks
Dithioketopyrrolopyrrole (blue pigment) is known to crystallize in three crystal phases I, II and III, among which only modification III exhibits an intense near-IR absorption. The mechanism of the near-IR absorption has been discussed on the basis of the crystal structure and exciton coupling effects. The J-aggregate-like molecular stack characterized by "bricks in a brick wall" is found to be responsible for the near-IR absorption. The switching of the near-IR absorptin by forming or disturbing the J-aggregate-like structure can be applied to an optical disk of the "write once" type. The disk developed exhibits a reflectivity change from about 30% to 45% on writing with a power of about 9mW at 780nm.
日本結晶学会誌 39(2), 188-194, 1997-04-28
The Crystallographic Society of Japan