Light-emitting characteristics of conjugated polymers

This article reviews mainly the results of our recent research on the relationship between the structure and the luminescence properties of PPV derivatives. PPV derivatives are particularly useful in an effort toward the establishment of such relationship because their chemical structures can be manipulated very systematically. Attachment of a wide variety of substituents, inclusion of kinky structural units, modification of main chain structures by inclusion of hole- and/or electron-transferring structures, and blending of polymers having different optical and electronic properties are representative approaches. The device characteristics of the light-emitting diodes (LEDs) fabricated from these polymers are discussed in relation to their structures. In certain cases, their photoluminescence (PL) properties are compared with their electroluminescence (EL) properties.