3,3,3',3'-tetramethyl-1,1'-bis(4-sulfobutyl)indocarbocyanine - 1 G

Squarylium dye (SQ), which is an analogue of cyanine dye, has a squaraine moiety in the center of the π-conjugate. The SQ dye has a zwitterion structure in which the cation and anion coexist in the molecule, although the cyanine dye has a separated cation component. The SQ was conventionally used as a charge generation material for an organic photo conductors. Recently, SQ provided a sensitizer for organic solar cells originating from a strong absorption in near infrared area. In addition, the SQ dye was applied to an organic light-emitting diode because it shows efficient red luminescence.