Fluorene-thiophene-5 ,5-dioxide copolymers

An increase in the PL QE of the fluorene-thiophene copolymers can be achieved by introduction of -oxidized thiophene units (although no efficient EL from such materials was reported). This aspect and the chemical structures of thiophene-iS,5 -dioxide-fluorene copolymers are discussed in more detail in Section 2.4. 

Beaupre and Leclerc reported fluorene-thiophene copolymers in which fluorene and thiophene-S,S-dioxide fragments 558 and 559 were separated by one or two thiophene units (02MI192). 

These copolymers are both p- and n-dopable, as follows from their electrochemistry, with bandgaps of 2.2 and 2.0 eV for 558 and 559, respectively. The efficiency of similar fluorene copolymers was much lower. The combination of thiophene and thiophene-S,S-dioxide units in a copolymers allows tuning of the emission color from green to pure red (02MI192 03SM(138)289). 

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