Light-emitting organic oligomer compositions
Photonic materials include light-emitting organic oligomer compositions that include at least one light-emitting oligomer. The oligomer compositions include oligofluorenes having chiral and/or achiral pendants. The oligomer compositions also include spiro-linked oligofluorenes and fully spiro-configured terfluorenes. Methods for syntheisizing light-emitting organic oligomer compositions include preparing fluorene-based oligomers by convergent/divergent synthesis.
1. A composition comprising a plurality of light-emitting organic oligomers, each of the oligomers comprising:
a first segment of fluorene residues in a first sequence;
a second segment of fluorene residues in a second sequence; and
an aromatic unit linking the first and second segments;
wherein the oligomers of the composition are substantially uniform in chain length and chemical composition.
2. The composition of claim 1 , wherein the first and second fluorene components each comprise at least one fluorene residue.
3. The composition of claim 2 , wherein each said at least one fluorene residue comprises two pendant groups in a 9-carbon position.
4. The composition of claim 3 , wherein at least one of the pendant groups is achiral.
5. The composition of claim 3 , wherein at least one of the pendant groups is chiral.
6. The composition of claim 3 , wherein the pendant groups are alkyl groups or alkoxy groups.
7. The composition of claim 3 , wherein the pendant groups comprise from about 2 to about 20 carbon atoms.
8. The composition of claim 3 , wherein at least one of the pendant groups has a branched structure.
9. The composition of claim 3 , wherein at least one of the pendant groups has a straight-chain structure.
10. The composition of claim 3 , wherein each said at least one fluorene residue is linked to at least one other fluorene residue or the aromatic component at a 2- carbon or a 7- carbon position.
11. The composition of claim 1 , wherein each of the first and second fluorene components comprises an endgroup selected from the group consisting of hydrogen, benzene and an alkyl group.
12. The composition of claim 1 , wherein the aromatic group is selected from the group consisting of:
13. The composition of claim 1 , wherein the oligomers are represented by the following formula:
where:
R 1 and R 2 are substituted or unsubstituted alkyl and/or alkoxy groups;
EG 1 and EG 2 are endgroups;
Ar is a group including one or more aromatic substituents; and
m and n are from about 0 to about 10 and m+n is at least 1;
x and y are from about 1 to about 5; and
(m+n)(x+y) is from about 2 to about 20.
14. The composition of claim 13 , wherein at least one of R 1 and R 2 is achiral.
15. The composition of claim 13 , wherein at least one of R 1 and R 2 is chiral.