Industrial applications of phthalocyanines

Phthalocyanines are the second most important class of colorant, and copper phthalocyanine is the single largest-volume colorant sold. Traditional uses of phthalocyanine colorants are as blue and green pigments for automotive paints and printing inks and as blue/cyan dyes for textiles and paper. Phthalocyanines have also found extensive use in many of the modern high technologies, e.g. as cyan dyes for ink jet printing, in electrophotography as charge generation materials for laser printers and as colorants for cyan toners. In the visible region, phthalocyanines are limited to blue, cyan and green colours. However, their absorption may be extended into the near infrared and by suitable chemical engineering it is possible to fingerprint the 700-1000 nm region. The properties and effects of these infrared-absorbing phthalocyanines are diverse and cover many important hi-tech applications, including photodynamic therapy, optical data storage, reverse saturable absorbers and solar screens.