The title compound is a commercial black pigment based on the perylene skeleton. It exhibits two distinct colors (red and black) in the solid state which correspond to an amorphous and a crystalline phase. The red color (500 nm) is due to randomly-oriented, individual molecules in the amorphous phase; whereas the black phase is composed of two absorption bands: one (473 nm) is due to individual molecules and the other (610 nm) is due to exciton coupling effects. The color change depends mainly on the appearance or disappearance of the absorption band around 610 nm. The present optical switching at 610 nm can be applied to an optical disk system based on an AlGaInP laser diode. An information storage system has been developed in which the absorption at 610 nm is switched on (red→black) or switched-off (black→red) on irradiation with laser in the presence of a hydrazone compound that induces a phase change.
Jin Mizuguchi, "Electronic Characterization of N,N′-Bis(2-phenylethyl)perylene-3,4:9,10-bis(di-carboximide) and its Application to Optical Disks" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP14), 1998, pp 516 - 519, https://doi.org/10.2352/ISSN.2169-4451.1998.14.1.art00045_2