BACKGROUND OF THE INVENTION

[0001] An OLED (organic light-emitting diode) is a light-emitting diode (LED), in which the emissive electroluminescent layer is a film of an organic compound, which emits light in response to an electric current. A typical OLED has a multi-layer structure, and typically includes an indium tin oxide (ITO) anode, and a metal cathode. Sandwiched between the ITO anode and the metal cathode are several organic layers, such as a hole injection layer (HIL), a hole transfer layer (HTL), an emitting material layer (EML), an electron transfer layer (ETL), and an electron injection layer (EIL). To facilitate hole injection, and achieve a smooth surface, a hole injection layer (HIL), located between an ITO anode and a hole transfer layer, is often desired. The most commonly used HIL material is poly(3,4- ethylenedioxythiophene)/poly(styrene sulfonic acid) complex (PEDOT/PSS). However, OLED fabricated from PEDOT PSS show a short life time due to corrosion, induced by the high acidity of the PEDOT/PSS. In addition, the PEDOT/PSS solution is often aqueous-based. When it is used in an OLED, trace moisture residue in the film may cause corrosion to the electrical circuit and lead to device decay. Thus, there is a continuous need for HIL materials, especially non-aqueous HIL compositions, for OLED application.

[0002] JP2008/111941A discloses an electrochromic device that is characterized by a pair of electrode structures having transparent electrodes formed on support substrates, which are disposed so that the transparent electrodes face each other via an electrolyte layer. A porous electrode, to which an electrochromic coloring material that develops a color by oxidation or reduction is adsorbed, is formed on at least one of the transparent electrodes in the pair of electrode structures; and a porous electrode carrying a ferrocene polymer compound having a predetermined structure is formed on the transparent electrode constituting the counter electrode structure.

[0003] CN178601 OAdiscloses a photochromic ferrocene diarylene compound. The ferrocene diarylene compound is a carrier switch material, and can be used as organic luminescent layer of OLED device [0004] Leung, Chem. Mater.. 20, 540-552 (2008) describes the use of ferrocene as one building block of an electrochemical polymerization monomer and the use of polymers prepared from these monomers as HIL in OLED. The active moiety for the HIL is triarylamine.

[0005] References that teach materials useful in electronic devices include WO 2010/082924 (cross-linkable copper phthalocyanine complex), WO 2011/120709 (quadratic planar mononuclear transition metal complexes), WO2004/041962(crosslinkable composite of boronic acid or a boronic acid derivative and an organic or organometallic moiety), US 2011/0198666 (p-dopant (Al, Be or Ir) with a matrix polymer, US 2008/073440 (crosslinkable composite of Ir), WO 2003/022008 (organic matrix doped with a metal complex), US 2005/0260444 (macrocyclic ligand coordinated to a metal center), and US 2009/0212280 (organic semiconducting matrix doped with a metal complex n-dopant).

[0006] However, as discussed above, there remains a need for new HIL materials, especially non-aqueous HIL compositions, for OLED applications.

SUMMARY OF THE INVENTION

[0007] The invention provides a composition comprising at least one dopant, and a polymer comprising at least one unit selected from Structure I:

(Structure I),

wherein M is selected from Fe, Co, or Ni;

Ri, R ₂ , R3, R4 and R5 are each independently selected from hydrogen; deuterium; halogen; substituted or unsubstituted (Ci-Ci ₆ ) alkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl; substituted or unsubstituted (C ₃ -Ci ₆ ) cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl;; substituted or unsubstituted (C6-Ci6) aryl fused with one or more cycloalkyl; 5- to 7-membered heterocycloalkyl fused with one or more substituted or unsubstituted aromatic rings or (C ₃ -Ci ₆ ) cycloalkyl fused with one or more substituted or unsubstituted aromatic rings; substituted or unsubstituted (Ci-Ci ₆ ) silyl; cyano; nitro; or hydroxy;

n is greater than or equal to 1 ; x is from 0 to 4; and

y is from 0 to 5.

[0008] The invention also provides a film comprising at least two layers, Layer A and Layer B, wherein Layer A is formed from a Composition A comprising a polymer comprising at least one unit selected from Structure I:

(Structure I),

wherein M is selected from Fe, Co, or Ni;

Ri, R ₂ , R3, R4 and R5 are each independently selected from hydrogen; deuterium; halogen; substituted or unsubstituted (Ci-Ci ₆ ) alkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl; substituted or unsubstituted (C ₃ -Ci ₆ ) cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl fused with one or more cycloalkyl; 5- to 7-membered heterocycloalkyl fused with one or more substituted or unsubstituted aromatic rings or (C ₃ -Ci ₆ ) cycloalkyl fused with one or more substituted or unsubstituted aromatic rings; substituted or unsubstituted (Ci-Ci ₆ ) silyl; cyano; nitro; or hydroxy;

n is greater than or equal to 1 ;

x is from 0 to 4; and

y is from 0 to 5.

[0009] The invention also provides an electronic device comprising at least one component formed from a Composition A comprising a polymer comprising at least one unit selected from Structure I:

(Structure I), wherein M is selected from Fe, Co, or Ni;

Ri, R ₂ , R3, R4 and R5 are each independently selected from hydrogen; deuterium; halogen; substituted or unsubstituted (Ci-Ci ₆ ) alkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl; substituted or unsubstituted (C ₃ -Ci ₆ ) cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl;; substituted or unsubstituted (C6-C16) aryl fused with one or more cycloalkyl; 5- to 7-membered heterocycloalkyl fused with one or more substituted or unsubstituted aromatic rings or (C ₃ -Ci ₆ ) cycloalkyl fused with one or more substituted or unsubstituted aromatic rings; substituted or unsubstituted (Ci-Ci ₆ ) silyl; cyano; nitro; or hydroxy;

n is greater than or equal to 1 ;

x is from 0 to 4; and

y is from 0 to 5.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is the H ¹ NMR of polyvinylferrocene (PVFC) in CDC1 ₃ .

[0011] Figure 2 is the cyclic voltammetry curve of PVFC solubilized in dimethylformamide (DMF)with 0.1 molar tetrabutylammonium hexafluorophosphate as the supporting electrolyte.

[0012] Figure 3 are the current-voltage curves of OLED Example 1 (PVFC), OLED Example 2 (PVFC+10% dopant), and Comparative example(polythiophene).

[0013] Figure 4 are the luminescence efficiency curves of OLED Example 1 (PVFC), OLED Example 2 (PVFC+10% dopant), and Comparative example (polythiophene).

[0014] Figure 5 are the luminescence decay curves of OLED Example 1 (PVFC), OLED Example 2 (PVFC+10% dopant), and Comparative example (polythiophene).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Overview

[0015] The HIL materials developed, to date, for OLED applications are largely limited to organic materials. To broaden the scope of HIL materials from which candidates can be chosen to meet the needs of various types of OLED device structures and applications, polymers with ferrocene in the side chain have been developed and used as HIL material. Surprisingly, these polymershave been found to be useful as HIL material, and OLED incorporating these polymers as HIL material exhibit good electroluminescent performance. Embodiments

[0016] As discussed above, in a first aspect,the invention providesa composition comprising at least one dopant, and a polymer comprising at least one unit selected from Structure I:

(Structure I),

wherein M is selected from Fe, Co, or Ni;

Ri, R ₂ , R ₃ , R4 and R ₅ are each independently selected from hydrogen; deuterium; halogen; substituted or unsubstituted (Ci-Ci ₆ ) alkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl; substituted or unsubstituted (C ₃ -Ci ₆ ) cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl fused with one or more cycloalkyl; 5- to 7-membered heterocycloalkyl fused with one or more substituted or unsubstituted aromatic rings or (C3-C16) cycloalkyl fused with one or more substituted or unsubstituted aromatic rings; substituted or unsubstituted (Ci-Ci ₆ ) silyl; cyano; nitro; or hydroxy;

n is greater than or equal to 1 ;

x is from 0 to 4; and

y is from 0 to 5.

[0017] An inventive composition may comprise a combination of two or more embodiments described herein.

[0018] In one embodiment, the dopant is a P-type dopant.

[0019] In one embodiment M in Structure I is Fe.

[0020] In one embodiment n of Structure I is from 1 to 1,000,000, or from 1 to 10,000, or from 1 to 1,000.

[0021] In one embodiment x and y of Structure I are both zero.

[0022] In one embodiment the halogen of at least one of, or at least two of, or at least three of, or all ofRi, R ₂ , R3, R*and Rsof Structure I is fluoride. [0023] In one embodiment the amount of polymer in the composition is from 1 weight percent (wt%) to 99wt%, or from 50wt% to 99wt%, or from 70wt% to 99wt%, based upon the weight of the composition.

[0024] In one embodiment the composition consists essentially of the polymer of Structure I and a P-type dopant.

[0025] In one embodiment the dopant of the composition is an organometal compound or an organometal salt. .

[0026] In one embodiment, the dopant is an organometal salt comprising at least one phenyl group. In a further embodiment, the anion component of the salt comprises a boron atom.

[0027] In one embodiment the organometal salt has a structure selected from one of the following:

combinations thereof.

[0028] In one embodiment the organometal salt has the structure:

[0029] In one embodiment the amount of dopant in the composition is from 1 weight percent (wt%) to 99wt%, or from lwt% to 50wt%, or from lwt% to 30wt%, based upon the weight of the composition.

[0030] In one embodiment, the amount of polymer in the composition is from 70 wt% to 99 wt%, and the amount of P-type dopant in the composition is from 1 wt% to 30 wt%, both based on the weight of the composition.

[0031] An inventive composition may comprise a combination of two or more embodiments described herein. [0032] The invention also provides a film comprising at least one layer formed from an inventive composition of one or more embodiments described herein.

[0033] The invention also provides an electronic device comprising at least one component formed from an inventive composition of one or more embodiments described herein.

[0034] The invention also provides, in a second aspect, a film comprising at least two layers, Layer A and Layer B, wherein Layer A is formed from a Composition A comprising a polymer comprising at least one unit selected from Structure I:

(Structure I),

wherein M is selected from Fe, Co, or Ni;

Ri, R ₂ , R3, R4 and R ₅ are each independently selected from hydrogen; deuterium; halogen; substituted or unsubstituted (Ci-Ci ₆ ) alkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl; substituted or unsubstituted (C ₃ -Ci ₆ ) cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl fused with one or more cycloalkyl; 5- to 7-membered heterocycloalkyl fused with one or more substituted or unsubstituted aromatic rings or (C ₃ -Ci ₆ ) cycloalkyl fused with one or more substituted or unsubstituted aromatic rings; substituted or unsubstituted (Ci-Ci ₆ ) silyl; cyano; nitro; or hydroxy;

n is greater than or equal to 1 ;

x is from 0 to 4; and

y is from 0 to 5.

[0035] An inventive film may comprises a combination of two or more embodiments described herein.

[0036] In one embodiment, Layer B is a hole transport layer.

[0037] In one embodiment Composition A comprises from 1 to 99weight percent (wt%) of at least one polymer comprising at least one unit selected from Structure I, based on the weight of the composition. In a further embodiment Composition A comprises from 50 to 99wt% of at least one polymer comprising at least one unit selected from Structure I, based on the weight of the composition. In a further embodiment, Composition A comprises from 70 to 99wt% of at least one polymer comprising at least one unit selected from Structure I, based on the weight of the composition.

[0038] In one embodiment, M of Structure I of the polymer of Composition A is Fe.

[0039] In one embodiment, n of Structure I of the polymer of Composition A is from 1 to 1 ,000, and both x and y of Structure I of the polymer of Composition A are zero.

[0040] In one embodiment, Layer A is in contact with Layer B.

[0041] In one embodiment, the film further comprises an emitting layer.

[0042] In one embodiment the thickness of Layer A is from 5nm to 500nm, or from 5nm to lOOnm, or from 5nm to 50nm, and the thickness of Layer B is from 5nm to 500nm, or from 5nm to lOOnm, or from 5nm to 50nm.

[0043] In one embodiment, Composition A further comprises a P-type dopant. In a further embodiment, the dopant is an organometal compound or an organometal salt.

[0044] In one embodiment, the dopant is an organometal salt comprising at least one phenyl group. In a further embodiment, the anion component of the salt comprises a boron atom. In a further embodiment, the organometal salt has a structure selected from one of the following:

, or combinations thereof.

[0045] In one embodiment the organometal salt has the structure:

[0046] In one embodiment the amount of dopant in Composition A is from 1 weight percent (wt%) to 99 wt%, or from 1 wt% to 50 wt%, or from 1 wt% to 30wt%, based upon the weight of the composition. [0047] An inventive film may comprise a combination of two or more embodiments described herein.

[0048] The invention also provides an electronic device comprising at least one layer formed from an inventive film of one or more embodiments described herein.

[0049] The invention also provides, in a third aspect, an electronic device comprising at least one component formed from a Composition A comprising a polymer comprising at least one unit selected from Structure

(Structure I),

wherein M is selected from Fe, Co, or Ni;

Ri, R ₂ , R3, R4 and R ₅ are each independently selected from hydrogen; deuterium; halogen; substituted or unsubstituted (Ci-Ci ₆ ) alkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl; substituted or unsubstituted (C3-C16) cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; substituted or unsubstituted (C ₆ -Ci ₆ ) aryl fused with one or more cycloalkyl; 5- to 7-membered heterocycloalkyl fused with one or more substituted or unsubstituted aromatic rings or (C ₃ -Ci ₆ ) cycloalkyl fused with one or more substituted or unsubstituted aromatic rings; substituted or unsubstituted (Ci-Ci ₆ ) silyl; cyano; nitro; or hydroxy;

n is greater than or equal to 1 ;

x is from 0 to 4; and

y is from 0 to 5.

[0050] An inventive electronic device may comprises a combination of two or more embodiments described herein.

[0051] In one embodiment, Composition A further comprises a P-type dopant. In a further embodiment, the dopant is an organometal compound or an organometal salt.

[0052] In one embodiment, the dopant is an organometal salt comprising at least one phenyl group. In a further embodiment, the anion component of the salt comprises a boron atom.In a further embodiment, the organometal salt has a structure selected from one of the following:

or combinations thereof.

[0053] In one embodiment the organometal salt has the structure:

[0054] In one embodiment the amount of dopant in Composition A is from 1 weight percent (wt%) to 99 wt%, or from 1 wt% to 50 wt%, or from 1 wt% to 30wt%, based upon the weight of the composition.

[0055] In one embodiment, M of Structure I of the polymer of Composition A is Fe.

[0056] In one embodiment, n of Structure I of the polymer of Composition A is from 1 to

1 ,000, and both x and y of Structure I of the polymer of Composition A are zero.

[0057] In one embodiment the electronic device further comprises a first electrode.

[0058] In one embodiment the electronic device further comprises a second electrode disposed over the first electrode.

[0059] In one embodiment the electronic device further comprises an organic layer disposed between the first and second electrodes.

[0060] In one embodiment, the at least one component, formed from Composition A, of the electronic device is an organic layer, which is disposed between the first and second electrodes.

[0061] In one embodiment, the electronic device further comprises a second Layer B.

[0062] In one embodiment, Layer B is a hole transport layer.

[0063] In one embodiment, Layer A is in contact with Layer B.

[0064] In one embodiment, the electronic device further comprises an emitting layer.

[0065] In one embodiment, the thickness of Layer A is from 5 nm to 50 nm, and the thickness of Layer B is from 5 nm to 50 nm. [0066] In one embodiment, the electronic device is an OLED (Organic Light Emitting Device).

[0067] In one embodiment the inventive composition may comprise a combination of two or more embodiments as described herein.

[0068] In one embodiment the inventive film may comprise a combination of two or more embodiments as described herein.

[0069] In one embodiment the inventive electronic device may comprise a combination of two or more embodiments as described herein.

Polymer Comprising Structure I

[0070] The following embodiments apply to all three aspects of the present invention, as discussed above.

[0071] The polymer comprising at least one unit selected from Structure I:

tructure I),

Wherein M, Ri, R ₂ , R3, R4 and R5, n, x and y are defined above (see Summary of Invention).

[0072] The polymer may comprise two or more embodiments as described herein.

[0073] In one embodiment Ri of Structure I is one of the following: hydrogen; deuterium; halogen; substituted or unsubstitutedCi-Ci ₆ alkyl; substituted or unsubstituted C ₆ -Ci ₆ aryl; substituted or unsubstituted C ₃ -Ci ₆ cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; or hydroxy.In a further embodiment, Ri of Structure I is one of the following: hydrogen; halogen; substituted or unsubstituted Ci-Ci ₆ alkyl; substituted or unsubstituted C ₆ -

[0074] In one embodiment R ₂ of Structure I is one of the following: hydrogen; deuterium; halogen; substituted or unsubstitutedCi-Ci6alkyl; substituted or unsubstituted C6-Ci6aryl; substituted or unsubstituted C ₃ -Ci ₆ cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; or hydroxy. In a further embodiment, R ₂ of Structure I is one of the following: hydrogen; halogen; substituted or unsubstitutedCi-Ci6alkyl; substituted or unsubstituted Ce-

[0075] In one embodiment R ₃ of Structure I is one of the following: hydrogen; deuterium; halogen; substituted or unsubstitutedCi-Ci ₆ alkyl; substituted or unsubstituted C6-Ci ₆ aryl; substituted or unsubstituted C ₃ -Ci ₆ cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; or hydroxy. In a further embodiment, R ₃ of Structure I is one of the following: hydrogen; halogen; substituted or unsubstitutedCi-Ci ₆ alkyl; substituted or unsubstituted C ₆ - [0076] In one embodiment R4 of Structure I is one of the following: hydrogen; deuterium; halogen; substituted or unsubstitutedCi-Ci ₆ alkyl; substituted or unsubstituted C ₆ -Ci ₆ aryl; substituted or unsubstituted C3-C16 cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; or hydroxy. In a further embodiment, R^of Structure I is one of the following: hydrogen; halogen; substituted or unsubstitutedCi-Ci ₆ alkyl; substituted or unsubstituted C ₆ -

[0077] In one embodiment R ₅ of Structure I is one of the following: hydrogen; deuterium; halogen; substituted or unsubstitutedCi-Ci ₆ alkyl; substituted or unsubstituted C ₆ -Ci ₆ aryl; substituted or unsubstituted C ₃ -Ci ₆ cycloalkyl; substituted or unsubstituted 5- to 7-membered heterocycloalkyl; or hydroxy. In a further embodiment, R ₅ of Structure I is one of the following: hydrogen; halogen; substituted or unsubstitutedCi-Ci ₆ alkyl; substituted or unsubstituted C ₆ -

[0078] In one embodiment n is from 1 to 1,000,000, further from 1 to 100,000, further from 1 to 10,000,and further from 1 to 1 ,000.

[0079] In one embodiment x is 0, or 1, or 2, or 3, or 4.

[0080] In one embodiment x is 0.

[0081] In one embodiment y is 0, or 1, or 2, or 3, or 4, or 5.

[0082] In one embodiment y is 0.

[0083] In one embodiment, the polymer comprises at least one unit selected from the following structures:

or combinations thereof, and wherein Me is methyl, and M, Ri, R ₂ , R3, Rt, R5, x, y and n are as previously described above.

[0084] In one embodiment the polymer of comprises at least one unit selected fromthe following structures:

or combinations thereof, and wherein Me is methyl, and M, Ri, R ₂ , R3, R4, R5, x, y and n are as previously described above.

[0085] In one embodiment the polymer comprises at least one unit selected from the following structures:

or combinations thereof, and wherein Me is methyl, and n is greater than or equal to 1 , or from 1 to 1,000,000, or from 1 to 100,000, or from 1 to 10,000, or from 1 to 1 ,000.

[0086] In one embodiment the polymer comprises at least one unit selected from the following structures:

H ₂

Fe

^**^ , or combinations thereof, and

wherein Me is methyl, and n is greater than or equal to 1, further from 1 to 1,000,000, further from 1 to 100,000, further from 1 to 10,000, and further from 1 to 1,000. [0087] In one embodiment the polymer comprises at least one unit selected from the following structures

or combinations thereof.

wherein Me is methyl, and n is greater than or equal to 1, further from 1 to 1,000,000, further from 1 to 100,000, further from 1 to 10,000, and further from 1 to 1,000.

[0088] "Heterocycloalkyl," and like terms, mean a cycloalkyl containing at least oneheteroatom for a cycloalkyl backbone atom, and carbon atom(s) for remaining cycloalkyl backbone atoms. Heteroatoms include, for example, B, N, O, S, P(=0), Si and P.

[0089] "Heteroaryl," and like terms, mean an aryl group containing at least oneheteroatom for an aryl backbone atom, and carbon atom(s) for remaining aryl backbone atoms. Heteroatoms include, for example, B, N, O, S, P(=0), Si and P.

[0090] Some examples of substituted groups include the following" deuterium, halogen, (C1-C30) alkyl with or without halogen substituent(s), (C6-C30) aryl, (C3-C30) heteroaryl with or without (C6-C30) aryl substituent(s), a 5- to 7-membered heterocycloalkyl containing one or more heteroatom(s) selected from, for example, B, N, O, S, P(=0), Si and P, a 5- to 7- membered heterocycloalkyl fused with one or more aromatic ring(s), (C3-C30) cycloalkyl, (C6- C30) cycloalkyl fused with one or more aromatic ring(s), tri(Cl-C30) alkylsilyl, di(Cl-C30) alkyl (C6-C30) arylsilyl, tri(C6-C30) arylsilyl, adamantyl, (C7-C30) bicycloalkyl, (C2-C30) alkenyl, (C2-C30) alkynyl, cyano, carbazolyl, NR ₂ iR ₂₂ , BR ₂₃ R ₂₄ , PR ₂₅ R ₂ e, P(=0)R ₂₇ R ₂₈ (wherein R ₂ i through R ₂₈ independently represent (C1-C30) alkyl, (C6-C30) aryl or (C3-C30) heteroaryl), (C1-C30) alkyl(C6-C30) aryl, (C1-C30) alkyloxy, (C1-C30) alkylthio, (C6-C30) aryloxy, (C6-C30) arylthio, (C1-C30) alkoxycarbonyl, (CI -C30) alkylcarbonyl, (C6-C30) arylcarbonyl, (C6-C30) aryloxycarbonyl, (C1 -C30) alkoxycarbonyloxy, (C1-C30) alkylcarbonyloxy, (C6-C30) arylcarbonyloxy, (C6-C30) aryloxycarbonyloxy, carboxyl, nitro and hydroxyl; or that the adjacent substituents are linked together to form a ring. Definitions

[0091] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are by weight. For purposes of United States patent practice, the contents of any referenced patent, patent application or publication are incorporated by reference m their entirety (or its equivalent U.S. version is so incorporated by reference) especially with respect to the disclosure of synthetic techniques, definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure), and general knowledge in the art.

[0092] "Polymer" and like terms mean a compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure and within the bulk polymer), and the term interpolymer as defined below. The polymer may contain trace amounts of residual catalyst residues.

[0093] "Interpolymer" and like terms mean a polymer prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus includes copolymers (employed to refer to polymers prepared from two different types of monomers), and polymers prepared from more than two different types of monomers.

[0094] "Comprising," "including," "having," and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, "consisting essentially of excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability. The term "consisting of excludes any component, step or procedure not specifically delineated or listed.

[0095] "Hole transport layer (HTL)," and like terms, mean a layer made from a material, which transports holes. High hole mobility is recommended. The HTL is used to help block passage of electrons transported by the emitting layer. Small electron affinity is typically required to block electrons. The HTL should desirably have larger triplets to block exciton migrations from an adjacent EML layer. Examples of HTL compounds include, but are not limited to, di(p-tolyl)aminophenyl]cyclohexane (TP AC), N,N-diphenyl-N,N-bis(3- methylphenyl)-l,l-biphenyl-4,4-diamine (TPD), and N,N '-diphenyl-Ν,Ν '-bis(l-naphthyl)- (1,1 '-biphenyl)-4,4'-diamine (NPB).

[0096] "Emitting layer" and like terms, mean a layer which consists of host and dopant. The host material could be bipolar or unipolar, and may be used alone or by combination of two or more host materials. The opto-electrical properties of the host material may differ to which type of dopant(Phosphorescent or Fluorescent) is used. For Fluorescent dopants, the assisting host materials should have good spectral overlap between adsorption of the dopant and emission of the host to induce good Foester transfer to dopants . For Phosphorescent dopants, the assisting host materials should have high triplet energy to confine triplets of the dopant.

[0097] "Dopant" and like terms, refer to an electron acceptor or a donator that increases the conductivity of an organic layer of an organic electronic device, when added to the organic layer as an additive. Organic semiconductors may likewise be influenced, with regard to their electrical conductivity, by doping. Such organic semiconducting matrix materials may be made up either of compounds with electron-donor properties or of compounds with electron-acceptor properties.

[0098] "P-type dopant" and like terms, refer to an electron acceptor that increases the conductivity of an organic layer of an organic electronic device, when added to the organic layer as an additive. Organic semiconductors may likewise be strongly influenced, with regard to their electrical conductivity, by doping. Such organic semiconducting matrix materials may be made up of either compounds with good electron-donor properties or compounds with good electron-acceptor properties. For doping electron-donor materials, strong electron acceptors, such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-l,4- benzoquinonedimethane (F4TCNQ) have become well known. By electron transfer processes, these produce so-called holes in electron donor-like base materials.

EXPERIMENTAL

/. Materials

[0099] The materials used in the following examples are reported in Table 1.

Table 1 : Materials Used in the Examples

II. Polymer Synthesis

Preparation of Acetylferrocene

[00100] To a solution of AICI ₃ (35g, 0.26mol), in 300mL dichloromethane, acryloly chloride (18.5g, 0.236mol), in 200mL dichloromethane, was added dropwise at 0°C, and the solution was allowed to warm up to room temperature, and stirred, until A1C1 ₃ dissolved. Then the solution was added dropwise into ferrocene (40g, 0.215mol), in 200mL dichloromethane, at 0°C. After addition, the solution was stirred at room temperature for 3hours. After reaction, the solution was added slowly into ice-water. The mixture (organic solution) was washed with water, 5 wt% NaHC0 ₃ (100 mL), dried over anhydrous MgS0 ₄ , and filtered. Concentration of the filtrate followed by silica column chromatography gave the corresponding product.

Ή NMR (CDCI ₃ , ppm): 6=4.775 (2H, H-Cp), 4.506 (2Η, H-Cp), 4.208 (5Η, H-Cp), 2.400 (3Η,

Preparation of l-(Ferrocenyl)ethanol

[00101] To a solution of acetylferrocene (lg, 4.4mmol), in lOOmL ethanol, sodium borohydride (0.8g, 2.1mmol) was added slowly, and then the solution was refluxed for 30 minutes. After that, 20mL of 6N sodium hydroxide was added, and the mixture continued to reflux for 15minutes. The solution was concentrated by removing the solvent under rotary evaporation. The residue was extracted with ether, and then dried with anhydrous magnesium sulfate. The solution was filtered, and then the solvent was removed by rotary evaporation. The product was further purified via silica column chromatography.1H NMR (CDCI ₃ , ppm):

6=4.548 (1Η, CH ₃ -CH-OH), 4.195 (9H, H-Cp), 1.848 (1Η, CH ₃ -CH-OH), 1.431 (3Η, CH ₃ -).

Preparation ofVinylferrocene The l-(Ferrocenyl)ethanol(0.92 g, 4mmol, 230), anhydrous copper sulfate (4.788 g, 30mmol, 159.6), and 10 mg of hydroquinone were dissolved in 100 ml of toluene. The mixture was refluxed for 45 minutes, and then cooled to room temperature. After the filtration, the solvent was removed under vacuum. The residue was extracted with ether, and dried with anhydrous magnesium sulfate. The solution was filtered, and then the solvent was removed via rotary evaporation. The product was further purified by silica column chromatography.

[00102] Ή NMR (COC , ppm): 6=6.453 (1H, -CH=CH ₂ ), 5.354 (1H, -CH=CH ₂ ), 5.030 (1Η, -CH=CH ₂ ), 4.347 (2Η, H-Cp), 4.199 (2Η, H-Cp), 4.097 (5Η, H-Cp).

Polymerization ofVinylferrocene

[00103] Vinylferrocene (l .OOg, 4.7mmol) and lOmg azobisisobutyronitrile (AIBN)were heated in an evacuated, sealed Pyrex tube at 80°C, for 3 hours. After the initial melt, an increase in viscosity was immediately observed, and after one hour, the tube contents were immobile. The polymer product was dissolved in tetrahydrofuran (THF) (10 mL). The polymer solution was then added dropwise to stirred methanol (200 mL), and the precipitated polymer was collected by filtration, re-dissolved in THF (30 mL), and re-precipitated into methanol (200 mL). Then the precipitated polymer was further purified by Soxhlet extraction using methanol for 48hours. The yellow, fibrous product(PVFC) was then dried in vacuum to afford 0.90 g(90%) of final product. The molecule weight was characterized using GPC, Mw=6.91 *10 ⁴ , Mn=1.38*10 ⁴ , ΡΟΙ=5.01.Ή NMR (CDC1 ₃ , ppm): 6=4.179 (2H, H-Cp), 3.512 (7Η, H-Cp), 1.066 (3Η, -CH-CH2-), see Figure 1.

777. Characterization and Measurement

GPC Analysis

[00104] The sample was dissolved in tetrahydrofuran FA(0.5wt%) and the concentration was2mg/mL. The sample appeared clear. The detailed experimental conditions were as follows: Instrument: Agilent 1200; Columns: Two Mixed B columns (7.8x300mm) in tandem; Column Temperature: 40°C; Mobile Phase: Tetrahydrofuran/FA(0.5%); Flow: l .O mL/min; Injection volume: 100 μί; Detector: Agilent Refractive Index detector, 40°C; Software: Agilent GPC software, and data was collected from duplicate injections; Calibration Curve: PL Polystyrene Narrow standards (Part No. :2010-0101) with molecular weights ranging from 1,480 to 3,787,000 g/mol. NMR Measurement

[00105] About20 mg of sample was dissolved in 0.6 mL of deuterated solvent, at room temperature, to get a homogenous solution. NMR data were acquired, at room temperature, on a Bruker AVANCE III 400 MHz spectrometer. A "5 mm BBI probe" was employed. Chemical shifts are given in parts per million (ppm) relative to tetramethylsilane (TMS).

Cyclic Voltammetry Measurement

[00106] Cyclic voltammetry was performed on a CHI 760D electrochemical work station, at room temperature, with a conventional three-electrode configuration, consisting of an Pt plate (diameter: 2mm) working electrode, a Pt wire counter electrode, and a Hg/Hg2+ reference electrode. DMF was used as solvent, and the supporting electrolyte was 0.1 M tetrabutylammonium hexafluorophosphate.

Polymer Film (No Dopant)

Atomic Force Microscope (AFM)

[00107] AFM was applied to visualize the surface morphology and determine the surface roughness of the spin coated HIL film. The AFM measurement was performed by a tapping mode on a Dimension V instrument produced by Veeco. In the AFM measurement, the deflection of the cantilever also generated a depth profile (or height profile) to show the vertical deviations along the surface in the nanometer range. The amplitude (A) of the vertical deviations was used to calculate the roughness of the surface. Ra and Rq are the most commonly used amplitude parameters to describe the surface roughness. Ra is the arithmetic average of absolute amplitude values, and Rq is the root mean square of the amplitude values, which are described as:

where Ai is the amplitude (height or depth) of a pixel i (means a point on the surface) in the AFM image, and n is the total number of pixels in the image. [00108] To determine the thickness of the spin coated film, part of the film was removed from the ITO substrate by a sharp blade, and then scanned by the cantilever. The thickness of the film was revealed by the gap between the two sections.

[00109] The surface roughness of the spin-coated PVFC on ITO was characterized by AFM.

[00110] The average roughness is reported in Table 2. After the spin-coated PVFC on ITO, the roughness was improved from 5.3 nanometer (nm) to 1.02 nm of Rq.

Table 2: Average Roughness of Spin-Coated PVFC

[00111] The HOMO (Highest Occupied Molecular Orbital)level was tested using cyclic voltammetry method. The CV-curve of PVFC in DMF solution is shown in Figure 5. From the oxidation peak, the HOMO can be estimated to -5.1—5.2 electron volts (eV).

IV. Composition

[00112] A composition was prepared by blending under ambient conditions (23 °C, atmospheric pressure) 1 grams (g) of PVFC and O.lg of TriphenylMethyltetrakis- (pentafluorophenyl)-borate (P-dopant).

V. OLED Fabrication and Testing

Fabrication

[00113] Glass substrates (20mm by 20mm) having a "3mm by 3mm" ITO area were cleaned with solvents (ethanol, acetone, isopropanol sequentially) and oxygen plasma. The ITO layer isl 50nm thick. The FflL solution in anisole/toluene at a 9:1 volume ratio(15 mg/mL, filter with 0.5micro polytetrafluoroethylene (PTFE) syringe filter) was spin-coated (speed: 2000 rpm), inside a nitrogen filled glove box, onto the ITO glass substrates. The spin-coated film was annealed at 150°C for 20minutes. The annealed film thickness was in the range of 10-lOOnm. These substrates were then transferred into a thermal evaporator, under a vacuum of approximately 1 *10 ^"7 Torr. The following layers :HTL1 , HTL2, Fl BlueEML, ETL and Lithium quinolate (Liq)were deposited, in sequence, with a thickness of 5nm, 25nm, 20nm,30nm and lnm,respectively. The deposition rates of organic layers were maintained at 0.05 to 0.1 nm/s. The aluminum cathode was deposited at 0.5nm/s. The active area of the OLED was "3 mm by 3 mm," as defined by the shadow mask for cathode deposition. The glass substrate (20 mm by 20 mm) was available from Samsung Corning with ITO layer thickness of 1 ,500 Angstrom (A). Finally, these OLED(reported in Table 3) were hermetically sealed prior to testing. The OLED have the following common structure:

HIL (400A±20A) HTL1 (50 A)/HTL2 (250 A)/F1 Blue EML(200A)/Alq3(300A)/Liq(10A).

Table 3 : Sample OLED

VI. Testing

[00114] The current- voltage-brightness (J-V-L) characterizations for the OLED were performed with a source measurement unit (KEITHLY 238) Luminescence meter (MINOLTA CS-100A). EL spectra of the OLED devices were collected by a calibrated CCD spectrograph. Current-voltage curves, luminescence efficiency curves, and luminescence decay curves of OLED Examples 1 and 2 and Comparative OLED Example 1 are shown in Figures3, 4and 5. The performance data were summarized in Table 4. It can be seen from Table 4: the turn-on voltage (Voltage at lOOOnit) of PVFC is close to Comparative example based on polythiophene; the life time of PVFC is longer than that of Comparative example based on polythiophene after doping with P-dopant; current efficiency of PVFC is the same with Comparative example based on polythiophene. In summary, OLED performance based on PVFC is comparable or even better than Comparative Example based on polythiophene.

Table 4. Performance summary of OLED devices.

[00115] It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.