Fluorene copolymers and devices made therefrom

Details Fluorene copolymers and devices made therefrom Fluorene copolymers and devices made therefrom

1999-04-09

2002-03-05

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From carboxylic acid or derivative thereof

C528S298000, C528S308000, C528S331000, C528S344000

Reexamination Certificate

active

06353083

ABSTRACT:

This invention relates to fluorene copolymers, polymer blends comprising such copolymers, and electronic devices (such as polymer light emitting diodes) containing one or more films derived from these copolymers.
Conjugated polymers may exhibit the optical and electronic properties of inorganic semiconductors because of the presence of delocalized p-electrons. Poly(9,9-disubstituted-fluorene-2,7-diyls) constitute a family of semiconducting polymers with advantageous features. Their aromatic backbone is resistant to chemical and photochemical degradation; the biphenylene unit of each fluorene monomer is locked into a planar-like configuration by the C9 atom; substituents on C9 may be chosen to modify physical and chemical properties without introducing torsional strain between adjacent fluorene units which would otherwise be disruptive to delocalization of the p-system. Indeed, poly(9,9-di-n-octylfluorene-2,7-diyl) of U.S. Pat. No. 5,708,130 (herein fully incorporated by reference) has been shown to be an effective emitter for a blue light emitting diode (LED) (Grice, et.al Applied Physics Letters, Vol. 73, 1998, p 629-631) and to exhibit high carrier mobility, a very desirable feature for electronic devices (Redecker, et. al Applied Physics Letters, Vol. 73, 1998, pp. 1565-1567) each of which are fully incorporated herein by reference.
A means to further modify their optical and electronic properties is desired in order to broaden the applicability of these fluorene polymers in electronic devices. In this context, optical properties of a polymer include its absorption and photoluminescence spectra and electronic properties include ionization potential, electron affinity, band gap and carrier transport and mobility. U.S. patent application Ser. No. 08/861,469 filed May 21, 1997, U.S. Pat. No. 6,169,163 (herein fully incorporated by reference) teaches a way for property modification via fluorene copolymers each containing 9,9-disubstituted fluorene and another comonomer. For instance, copolymers comprising fluorene and aromatic amines have lower (closer to vacuum level) ionization potential and preferential hole transporting properties, and copolymers with cyano-containing moieties have higher electron affinity and preferential electron transporting properties relative to fluorene homopolymers.
Many electronic applications require the active material to exhibit both hole transporting and electron transporting properties. To maximize the efficiency of a LED, for example, the polymer should ideally transport both holes and electrons equally well (Bradley et. al, in Springer Series in Solid State Sciences, Vol 107, Springer-Verlag Berlin Heidelberg, 1992, pp. 304-309). The copolymers of U.S. patent application Ser. No. 08/861,469 filed May 21, 1997, herein fully incorporated by reference, comprising a fluorene moiety and one other comonomer cannot meet this requirement; therefore, there is a need for further improvement.
This invention relates to copolymers of 9-substituted and/or 9,9-disubstituted fluorene moieties and at least two other comonomers containing delocalized p-electrons. Preferably, at least 10% of the total monomeric units of these copolymers are selected from 9-substituted- and/or 9,9-disubstituted fluorenes; more preferably at least 15% of the monomeric units of these copolymers are selected from 9-substituted- and/or 9,9-disubstituted fluorenes; and most preferably at least 20% of the monomeric units of these copolymers are selected from 9-substituted- and/or 9,9-disubstituted fluorenes. Each copolymer contains two or more non-fluorene comonomers in any proportion. These copolymers are characterized by their excellent solubility (>1 g/L) in common organic solvents, ability to form pin-hole free films and weight-average molecular weight of at least 3000 gram/mole relative to polystyrene standard, preferably at least 10,000 gram/mole, most preferably at least 20,000 gram/mole. They are further characterized by a polydispersity of less than 10, preferably less than 5, most preferably less than 3. These copolymers exhibit photoluminescent emission in the range of 350 nm to 1,000 nm and absorption from 200 nm to 600 nm. The copolymers of this invention are useful as the active components in electronic devices including light emitting diodes, photocells, photoconductors, and field effect transistors.
This invention relates to fluorene copolymers and electronic devices comprising a film of such copolymers. The subject copolymers comprise at least 10%, based on residual monomeric units (RMU), of 9-substituted and/or 9,9-disubstituted fluorene moieties represented by structures I and II respectively. A residual monomeric unit is the portion of the monomer that is incorporated into the polymer backbone. For instance, 1,4-phenylene is the residual monomeric unit of 1,4-difunctional-benzene monomers irrespective of the chemical nature of the functional groups.
In structures I and II, R
1
and R
2
are independently in each occurence hydrogen, C
1-20
hydrocarbyl, C
1-20
hydrocarbyloxy, C
1-20
thiohydrocarbyloxy, or cyano. R
1
and R
2
are independently in each occurrence preferably hydrogen, C
1-20
alkyl, C
6-10
aryl or alkyl-substituted aryl, C
6-10
aryloxy or alkyl-substituted aryloxy, C
1-12
alkoxy/thioalkoxy, and cyano. Even more preferably R
1
and R
2
are independently in each occurrence hydrogen, C
1-10
alkyl, phenyl, and cyano. R
3
and R4 are independently in each occurrence a hydrogen, C
1-20
hydrocarby optionally substituted with C
1-20
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters; C
6-20
aryl optionally substituted with C
1-20
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters. R
3
and R
4
may also form C
3-12
cyclic structures with the olefin carbon (structure I) to which they are attached, said cyclic structures may further contain one or more heteroatoms such as phosphorus, sulfur, oxygen and nitrogen. Preferably R
3
and R
4
are independently in each occurrence a hydrogen, C
1-12
alkyl optionally substituted with C
1-12
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano and esters; C
6-20
aryl optionally substituted with C
1-12
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters. Most preferably R
3
and R
4
are independently in each occurrence a hydrogen, C
1-8
alkyl optionally substituted with C
1-10
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters; C
6-12
aryl optionally substituted with C
1-10
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters. R
5
and R
6
are independently in each occurrence a hydrogen, C
1-20
hydrocarby optionally substituted with C
1-20
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters; C
6-20
aryl optionally substituted with C
1-20
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters. R
5
and R
6
may also form C
3-12
cyclic structures with the C-9 carbon of fluorene (structure II), said cyclic structures may further contain one or more heteroatoms such as phosphorus, sulfur, oxygen and nitrogen. Preferably R
5
and R
6
are independently in each occurrence a hydrogen, C
1-12
alkyl optionally substituted with C
1-12
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano and esters; C
6-20
aryl optionally substituted with C
1-12
alkoxy/aryloxy, thioalkoxy/thioaryloxy, secondary/tertiary amines, hydroxy, carboxylic/sulfonic acids, cyano, and esters. Most preferably R
5
and R
6
are independently in each occurrence a hydrogen, C
1-8
alkyl optionally substituted with C
1-10
alkoxy/aryloxy, thioalkox

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