A litany of new materials
1: The prototypical (green) fluorescent polymer is poly(p-phenylene vinylene)
2 & 3: Two best known (orange-red) solution processible conjugated polymers MEH-PPV (2) and ``OC1C10'' PPV (3).
4: Copolymers have been widely developed because they allow color tuning and can show improved luminescence. 
5 & 6: Cyano-derivatives of PPV 5 and 6 show increased electron affinities and are used as electron transport materials.
7: Blue emitters include high-purity polymers such as poly(dialkylfluorene)s.
8 & 9:  `Doped' polymers such as poly(dioxyethylene thienylene), PEDOT (8), doped with polystyrenesulphonic acid, PSS (9), are widely used as hole-injection layers.