KR100974008B1 - Phosphorescent polymer and organic light emitting device having the same - Google Patents

Abstract

PURPOSE: A phosphorescent polymer is provided to obtain excellent luminescent properties and very high external quantum efficiency, to form a thin film without defects using a wet process due to very superior solubility to an organic solvent, and to improve thermal durability of an organic electroluminescent device including the same. CONSTITUTION: A phosphorescent polymer includes a functional group containing an iridium complex with a structure of phenylpyridine or phenylisoquinoline on a backbone containing a non-conjugated polymer. The phosphorescent polymer contains a structure unit containing a metal complex. The phosphorescent polymer is marked by chemical formula 1 or chemical formula 2. An organic electroluminescent device has an electroluminescent layer including the phosphorescent polymer.

Description

Phosphorescent polymer and organic electroluminescent device comprising same {PHOSPHORESCENT POLYMER AND ORGANIC LIGHT EMITTING DEVICE HAVING THE SAME}

TECHNICAL FIELD The present invention relates to the field of displays, and more particularly, to a phosphorescent polymer and an organic electroluminescent device comprising the same.

Recently, the interest of phosphorescent materials for manufacturing organic light emitting devices (OLEDs) has been increasing. This is because the maximum internal quantum efficiency of the phosphor is close to 100%.

However, high efficiency phosphor materials that can be applied to organic electroluminescent devices are very limited. That is, the development of phosphorescent materials using transition metals such as Eu, Tb, Ru, Rh, Os, etc., is progressing, but they have a low luminance and low stability (phase separation), so there is a limit to applying them to actual devices.

For this reason, research on a novel light emitting material is being actively conducted. Among them, studies are being conducted to bind iridium having high luminous efficiency as a dopant to an alkyl group chain of polyfluorene which is a conjugated polymer.

However, conjugated polymers containing such phosphorescent dopants have somewhat lower quantum efficiencies than those using low molecular hole materials and phosphorescent dopants. This is because the conjugated polymer has a lower triplet energy state than the phosphorescent dye, and the emitted triplet energy returns to the hole conjugated polymer. In addition, the transfer of thermal energy from the phosphorescent dopant to the hole conjugated polymer reduces the phosphorescence efficiency of the OLED.

Therefore, in order to achieve high external quantum efficiency, it is necessary to develop a new hole polymer having no low triplet energy state and no phosphorescence phenomena.

One aspect of the present invention provides a phosphorescent polymer having excellent luminescent properties and an organic electroluminescent device comprising the same.

One aspect of the present invention provides a phosphorescent polymer that can be formed by a wet method and an organic electroluminescent device comprising the same.

One aspect of the present invention provides an organic electroluminescent device having improved durability and long life time.

Phosphorescent polymer according to an aspect of the present invention is bonded to an iridium complex containing group having a phenylpyridine or phenylisoquinoline structure in the main chain containing a non-conjugated polymer.

On the other hand, the organic electroluminescent device according to an aspect of the present invention has a light emitting layer comprising the phosphorescent polymer.

The phosphorescent polymer according to an aspect of the present invention may exhibit very high external quantum efficiency while exhibiting excellent luminescence properties. In addition, the phosphorescent polymer is very excellent in solubility in organic solvents generally used to form a defect-free thin film by the wet method. In addition, since the phosphorescent polymer is thermally stable and can emit light for a long time, the thermal durability of the organic electroluminescent device including the same can be improved and its life can be extended.

Hereinafter, a phosphorescent polymer according to an aspect of the present invention and an organic electroluminescent device including the same will be described in detail.

Phosphorescent polymer according to an aspect of the present invention is an iridium complex containing group having a phenylpyridine (ppy) or phenylisoquinoline (piq) structure is bonded to the main chain containing a non-conjugated polymer.

The phosphorescent polymer may contain a metal complex-containing structural unit represented by any one of the following Formulas 1a to 1d.

In Formula 1a, A represents a non-conjugated polymer, D represents a single bond or an oxygen atom, a phenylene group, an alkylene group or an alkoxylene group, L represents an organic ligand, w is an integer of 1 to 3, d is 1 Or two.

In Formula 1b, A represents a non-conjugated polymer, D represents a single bond or an oxygen atom, a phenylene group, an alkylene group or an alkoxylene group, L represents an organic ligand, w is an integer of 1 to 3, d is 1 Or two.

In formula (1c), A represents a nonconjugated polymer, L represents an organic ligand, w is an integer of 1 to 3.

In Formula 1d, A represents a nonconjugated polymer, L represents an organic ligand, w is an integer from 1 to 3.

The phosphorescent polymer preferably has a content ratio of 0.1 to 10 mol% of the metal complex-containing structural unit.

The phosphorescent polymer preferably has at least one of a carbazole (Cz) skeleton and a triphenylamine (TPA) skeleton in the molecule, but is not limited thereto.

In the phosphorescent polymer, the A in the metal complex-containing structural unit is preferably a non-conjugated polymer having at least one of a carbazole skeleton and a triphenylamine skeleton, but is not limited thereto.

The method of preparing the phosphorescent polymer may include reacting a metal complex-containing compound with a nonconjugated polymer, but is not limited thereto.

The organic electroluminescent device according to an aspect of the present invention may have a light emitting layer formed by the above-described phosphorescent polymer, but is not limited thereto. Here, the organic electroluminescent device may be an anode / light emitting layer / cathode, an anode / hole injection layer / (hole transport layer) / light emitting layer / cathode, an anode / light emitting layer / electron injection layer / (electron transport layer) / cathode, anode / hole injection layer / It may have any one of a structure such as (hole transporting layer) / light emitting layer / electron injection layer / (electron transporting layer) / cathode. In addition, the organic electroluminescent device may be a tandem type or triple type, in which case the structures may be stacked in the same manner, or heterogeneous structures may be stacked.

The metal complex-containing compound used as the monomer for obtaining the phosphorescent polymer according to one aspect of the present invention is at least one of a metal complex-containing group having a phenylpyridine structure and a metal complex-containing group having a phenylisoquinoline structure in the nonconjugated polymer. The metal complex-containing group of the species is bound, but is not limited thereto.

As the metal complex-containing compound, an iridium complex having a bipyridyl (BP) and a triphenylamine or carbazole structure as a hole transporting material in the main chain is a living radical polymerization by nitroxide (Nitroxide Mediated Radical Polymerization: NMRP). May be combined with the phosphorescent polymer.

Cyclometallate iridium (III) according to one aspect of the present invention may have a high external quantum efficiency as a phosphorescent dopant.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the technical spirit of the present invention is not limited or limited thereto.

Example 1: Initiator (Compound-1) Synthesis

The reaction initiator (Compound-1) is 2-hydroxyethyl phenyl Tetramethylpiperidinooxy and 4,4'-bis-chloromethyl- (2,2 ') bipyridinyl as shown in Scheme 1 below. (4,4'-bis-chloromethyl- (2,2 ') bipyridinyl) was synthesized. Identification of the new nitroxide material was carried out by mass spectrometry and ¹ H-NMR.

Example 2: Monomer Synthesis

Example 2-1: Compound-2 Synthesis

Diphenyl- [4- (4-vinyl-benzyloxymethyl) -phenyl] -amine (Diphenyl- [4- (4-vinyl-benzyloxymethyl) -phenyl] -amine), which is Compound-2, was synthesized through Scheme 2 below. It was.

Example 2-2: Compound-3 Synthesis

Carbazole monomers to which the styrene-linked compound-3 was synthesized were synthesized in a yield of 80% or more through the following Scheme 3.

Example 3: Synthesis of Iridium Complex

Example 3-1: Compound-5 Synthesis

As shown in Scheme 4, [Ir (ppy) ₂ Cl] ₂ (Compound-4) is reacted by reacting phenylpyridine ligand and iridium chloride hydrate with ethoxyethanol through a general synthetic reaction in water. a synthesized following the synthetic compounds -4 in acetonitrile with phosphate mate eumyionreul hexafluoro through substitution of cyanide groups _{[Ir (ppy) 2 (NC} -CH 3) 2] + PF 6 - ( compound -5 ) Was synthesized.

Example 3-2: Compound-8 Synthesis

As shown in Scheme 5, Compound-6 (phenylisoquinoline: pig) ligand and iridium chloride hydrate are reacted with ethoxyethanol through a general synthetic reaction in water to give [Ir (piq) ₂ Cl] ₂ ( Compound-7) was synthesized, and then the synthesized compound-7 was substituted with [Ir (piq) ₂ (NC-CH ₃ ) ₂ ] ⁺ PF ₆ through substitution of a cyanide group in acetonitrile having a hexafluorophosphate counter anion. ^- (Compound-8) was synthesized.

Example 4: Synthesis of Iridium Complex Compound

Example 4-1: ^ppy Synthesis of Ir-BP

_{[Ir (ppy) 2 (NCCH} 3) 2] + PF 6 - ( compound -5) (160 mg, 0.22mmol) and 4,4'-dimethyl-bipyridine (36.8 mg, 0.20 mmol) in dichloromethane (10 mL Solution), and stirred under nitrogen for 2 hours. The resultant was then re-solution in dichloromethane (2 mL) and added dropwise to pentane (100 mL). Thereafter, the generated precipitate was filtered and washed with pentane. Thereafter, the resulting solid was dried under vacuum at room temperature to obtain the title compound (see Scheme 6 below).

¹ H NMR (300 MHz, CDCl ₃ ) δ 8.60 (m, 2 H), 7.91 (d, J = 8.1 Hz, 2 H), 7.74 (m, 4H), 7.67 (d, J = 8.1 Hz, 2H) , 7.53 (d, J = 5.7 Hz, 2H), 7.16 (d, J = 5.4 Hz, 2H), 7.03 (t, J = 6.9 Hz, 4H), 6.90 (t, J = 6.3 Hz, 2H) , 6.30 (d, J = 7.5 Hz, 2H), 2.61 (br s, 6H)

Example 4-2: ^piq Synthesis of Ir-BP

_{[Ir (piq) 2 (NCCH} 3) 2] + PF 6 - ( compound -8) (180 mg, 0.22 mmol ) and 4,4'-dimethyl-bipyridine (36.8 mg, 0.20 mmol) in dichloromethane (10 mL Solution), and stirred under nitrogen for 2 hours. The resultant was then re-solution in dichloromethane (2 mL) and added dropwise to pentane (100 mL). Thereafter, the generated precipitate was filtered and washed with pentane. Thereafter, the resulting solid was dried under vacuum at room temperature to obtain the title compound (see Scheme 7 below).

¹ H NMR (300 MHz, CDCl ₃ ) δ 8.93 (m, 2 H), 8.57 (s, 2 H), 8.26 (d, J = 8.1 Hz, 2 H), 7.90 (m, 2H), 7.77 (m , 4H), 7.55 (d, J = 5.4 Hz, 2H), 7.41 (q, J = 14 Hz and 6.3 Hz, 4H), 7.13 (m, 2H), 6.88 (t, J = 7.5 Hz, 2H) , 6.30 (d, J = 6.9 Hz, 2H), 2.59 (br s, 6H).

Example 5: Polymer Synthesis

Example 5-1 Synthesis of BP-TPA

The reaction proceeded through the bulk monomer compound-2 with diphenyl ether using compound-1 as an initiator (see Scheme 8 below). By using such mobile radical polymerization, a good polymer having a low polydispersity index (PDI) was obtained. The BP-TPA polymer obtained as follows was composed of triphenylamine having a side chain bonded to styrene through an oxygen atom, and a functional group having excellent hole transport, and also had a structure in which TEMPO (Tetramethylpiperidinooxy) nitroxy existed at the end.

Example 5-2: Synthesis of BP-Cz

The reaction proceeded through the bulk monomer compound-3 with diphenylether using compound-1 as the initiator (see Scheme 9 below). By using such mobile radical polymerization, a good polymer having a low polydispersity index (PDI) was obtained. The BP-Cz polymer obtained as follows was composed of a carbazole group, which is well known as a hole transporting material, and had a structure in which TEMPO (Tetramethylpiperidinooxy) nitroxy existed at its end.

Example 6: Complexation of Polymers Through Bipyridine

Example 6-1: ^ppy Synthesis of Ir-TPA

[Ir (ppy) ₂ (NCCH ₃ ) ₂ ] ⁺ PF ₆ ⁻ (Compound-5) (40 mg, 0.055 mmol) and BP-TPA polymer (100 mg) in solution with dichloromethane (10 mL), The mixture was stirred at room temperature under nitrogen for 2 hours. At this time, the color of the solution changed from yellowish brown to ocher color as the reaction proceeded. Thereafter, the resultant was concentrated, dissolved in dichloromethane (2 mL), and then added dropwise to methanol (300 mL). Thereafter, the generated precipitate was filtered and washed with methanol. Thereafter, the resulting solid was dried under vacuum at room temperature to obtain the title compound (see Scheme 10 below).

¹ H NMR (300 MHz, CDCl ₃ ) δ 8.54 (br s, bipyridine H ), 8.28 (br s, bipyridine H ), 7.86 (br s, Ar H ), 7.68 (br s, Ar H ), 7.45 (br s, Ar H), 7.24 ( br m, Ar H), 7.08 (br s, Ar H), 4.60-4.30 (br m, - C H 2 OC H 2 -), 3.53 (br m, - OC H 2 -), 2.00-0.80 (br m, - C H 2 C H-).

Example 6-2: ^ppy Synthesis of Ir-Cz

_{[Ir (ppy) 2 (NCCH} 3) 2] + PF 6 - and then the solution Chemistry (Compound -5) (40 mg, 0.055 mmol ) and BP-Cz polymer (100 mg) in dichloromethane (10 mL), The mixture was stirred at room temperature under nitrogen for 2 hours. At this time, the color of the solution changed from yellowish brown to ocher color as the reaction proceeded. Thereafter, the resultant was concentrated, dissolved in dichloromethane (2 mL), and then added dropwise to methanol (300 mL). Thereafter, the generated precipitate was filtered and washed with methanol. Thereafter, the resulting solid was dried under vacuum at room temperature to obtain the title compound (see Scheme 10 below).

¹ H NMR (300 MHz, CDCl ₃ ) δ 8.26 (br s, Ar H ), 8.08 (br m, bipyridine H ), 7.15 (br m, Ar H ), 6.99 (br s, aromatic H ), 4.50-4.20 _{(br m, - C H 2} OC H 2 -), 3.39 (s, 2 H), 2.00-0.

Example 6-3: ^piq Synthesis of Ir-TPA

_{[Ir (piq) 2 (NCCH} 3) 2] + PF 6 - and then the solution Chemistry (Compound -8) (60 mg, 0.075 mmol ) and BP-TPA polymer (80 mg) in dichloromethane (10 mL), The mixture was stirred at room temperature under nitrogen for 2 hours. Thereafter, the resultant was concentrated, dissolved in dichloromethane (2 mL), and then added dropwise to methanol (300 mL). Thereafter, the generated precipitate was filtered and washed with methanol. Thereafter, the resulting solid was dried under vacuum at room temperature to obtain the title compound (see Scheme 11 below).

¹ H NMR (300 MHz, CDCl ₃ ) δ 8.46 (br m, bipyridine H ), 8.08 (br m, bipyridine H ), 7.15 (br m, aromatic H ), 6.99 (br s, aromatic H ), 4.50-4.20 _{(br m, - C H 2} OC H 2 -), 3.39 (s, 2 H), 2.00-0.70 (br m, - C H 2 C H-).

Example 6-4: ^piq Synthesis of Ir-Cz

_{[Ir (piq) 2 (NCCH} 3) 2] + PF 6 - ( compound -8) (40 mg, 0.048 mmol ) and BP-Cz polymer (80 mg) with nitrogen and then a solution Chemistry in dichloromethane (10 mL) Stir at room temperature for 2 hours. At this time, the color of the solution changed from yellowish brown to ocher color as the reaction proceeded. Thereafter, the resultant was concentrated, dissolved in dichloromethane (2 mL), and then added dropwise to methanol (300 mL). Thereafter, the generated precipitate was filtered and washed with methanol. Thereafter, the resulting solid was dried under vacuum at room temperature to obtain the title compound (see Scheme 11 below).

¹ H NMR (300 MHz, CDCl ₃ ) δ 8.46 (br m, bipyridine H ), 8.08 (br m, bipyridine H ), 7.15 (br m, aromatic H ), 6.99 (br s, aromatic H ), 4.50-4.20 (br m, -C H ₂ OC H _2- ), 3.39 (s, 2 H ), 2.00-0.70 (br m, -C H ₂ C H- ).

The yield of the iridium polymer obtained through Example 6 as described above was 80 to 90%. Since the iridium polymer was easily dissolved in a general organic solvent, the iridium polymer solution could be formed on a thin film in the same manner as spin coating.

Physical property evaluation

Absorbance, optical and electrochemical properties of various compounds were measured and the results were evaluated as follows.

Optical properties evaluation

1 is a graph showing ultraviolet-visible light absorption spectra of wavelengths in the solid state of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA and ^piq Ir-Cz.

Referring to FIG. 1, all the absorption spectra of the iridium complex were significantly higher than the general hole transport material. The iridium polymers of ^ppy Ir-TPA and ^piq Ir-TPA showed strong absorption bands at 306 nm, which can be attributed to the π-π * exciter state of TPA. On the other hand, ^ppy Ir-Cz and ^piq Ir-Cz containing carbazole showed perfect absorption bands at 270 to 350 nm due to the π-π * exciton state of carbazole.

Figure 2 is a graph showing the ultraviolet-visible absorption spectrum according to the wavelength of the monomers, ^ppy Ir-BP, ^ppy Ir-BP in chloroform.

Referring to FIG. 2, it can be determined that weak bands are observed at long wavelengths (380 to 450 nm) due to charge transfer of ppy (or piq ) at Ir. In addition, this low energy absorption can be judged by MLCT (charge transfer between metal and ligand).

Figure 3 is a graph showing the emission spectrum in the solid state of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA and ^piq Ir-Cz.

Referring to FIG. 3, all of the complexes showed strong luminescence not only in the organic solvent phase but also in the solid state. Although BP-TPA and BP-Cz did not show luminescence at the long wavelength of the UV lamp, ^ppy BP-TPA and ^ppy BP-Cz showed luminescence. Through this, yellow light emission was found to be due to the cyclometalate iridium complex of the polymer structure. On the other hand, when the emission spectrum was excited at 400 nm, the emission spectrum showed a gentle emission band at 570 to 590 nm depending on the type of ligand.

Thermal characteristic evaluation

4 is a graph showing the change in weight with temperature as a result of thermal analysis of BP-TPA, ^ppy Ir-TPA and ^ppy Ir-Cz.

Referring to FIG. 4, in the case of BP-TPA without iridium complex, pyrolysis began to occur at 200 ° C., and a weight loss of 5% was observed at 230 ° C. FIG. The phosphor iridium complex polymer showed a weight loss of 5% at 250 ° C., thus confirming relatively high thermal stability. Through this, it was found that there is thermal stability of the phosphor iridium complex polymer and there is no thermal effect of the iridium complex.

Electroluminescence Characteristics Evaluation

5 is a graph showing current density according to voltage and luminance according to voltage in an organic electroluminescent device. Here, the organic electroluminescent element used was composed of ITO / Ir-polymer / BCP / Alq ₃ / Al. 6 is a graph showing the external quantum efficiency according to the current density of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA and ^piq Ir-Cz.

Referring to FIG. 5, the current density in the device using ^ppy Ir-TPA as the light emitting layer was higher than that in the device using ^ppy Ir-Cz as the light emitting layer. In addition, when ^ppy Ir-TPA was used as the light emitting layer, the maximum luminance was higher than 100 cd / m ^{2 at 32 V} , whereas when ^ppy Ir-Cz was used as the light emitting layer, it was lower than 10 cd / m ² . In addition, as shown in FIG. 6, the external quantum efficiency was 1.0% higher than that of the device using ^piq Ir-Cz. Based on these results, it was found that triphenylamine was much superior to carbazole as the hole transport material.

In order to investigate the effects on the brightness, quantum efficiency and energy efficiency of the hole transport layer, poly (p-phenylenevinylene) (PPV) or poly (3,4-ethylenedioxythiophene) (PEDOT) was inserted on the ITO as the hole transport material. The array was constructed.

FIG. 7 is a graph showing the external quantum efficiency of PLED containing ^ppy Ir-TPA and ^piq Ir-TPA and using PPV as the hole injection layer, where PLED is ITO / PPV / Ir-polymer / BCP / Alq ₃ / Al. Configured. FIG. 8 is a graph showing the external quantum efficiency of PLED containing ^ppy Ir-Cz and ^piq Ir-Cz and using PEDOT as the hole injection layer, where PLED is ITO / PEDOT / Ir-polymer / BCP / Alq ₃ / Al. Configured.

Referring to FIG. 7, it can be seen that the current density is lower in the device using PPV than the device configured without the PPV, and the maximum luminance at 30V is also lower than 40 cd / m ² . In addition, the maximum quantum efficiency of the device using PPV was found to be 0.06 to 0.2%.

Referring to FIG. 8, the device using PEDOT was similar in current density to the device using PPV, but the electroluminescence was very low.

As a result, it can be seen that the lower effect is shown when the device than the hole-transfer material. This is because the efficiency decreases as the current density increases due to triplet-triplet extinction. Even when the phosphorescent polymer is used as the light emitting layer, the operating voltage of 1 cd / m ² is 21 V when composed of two kinds of hole transport materials (TPA, Cz) and two kinds of ligands (ppy, piq). This can be explained by the presence of styrene of monomer compound-2 and compound-3. In other words, Styrene is a well-known insulator because it does not have charge injection and charge transfer characteristics.

The luminescence of the iridium polymer can be explained by the energy transfer from the singlet or triplet excited state of the phosphor to the triplet excited state. Typical luminescence involves energy transfer from the triphenylamine or carbazole to the iridium complex in the excited state, and the injected holes and charges must be recombined in the emitting layer.

9 is a graph showing electroluminescence spectra of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA, and ^piq Ir-Cz.

9, each peak showed yellow-red 610 nm red and 640 nm red light depending on the type of ligand.

10 is a graph showing color coordinates of each polymer on an organic electroluminescent device. Here, the organic electroluminescent device was composed of ITO / Ir-polymer / BCP / Alq ₃ / Al.

Referring to FIG. 10, the color coordinates of the organic electroluminescent device including ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA, and ^piq Ir-Cz are respectively (0.51,0.48), (0.55,0.45), and ( 0.58,0.41) and (0.60,0.38).

Electrochemical Characterization

11 is a graph showing cyclic voltage current values of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA, and ^piq Ir-Cz.

The redox potential of the polymer film was determined by cyclic voltammetry (CV), and a working electrode, a counter electrode, and an Ag / Ag ⁺ (0.01 M in ACN) reference electrode were used. All electrochemical data were measured based on domestic Fc ⁺ / Fc.

As shown in (a) of FIG. 11, the oxidation process of ^ppy Ir-TPA started at 0.40 V and peaked at 0.56 V and 0.62 V, thereby improving the hole injection ability of the polymer.

The oxidation process is closely related to the injection of holes, ie the movement of electrons, in the metal HOMO. On the other hand, the sulfur source of ^ppy Ir-TPA started at -1.14V and peaked at -1.37V. This suggests that the oxidation process is due to the triphenylamine moiety but the reduction is due to the pyridyl ring of the ligand.

Energy level assessment

12 is a graph showing electron energy of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA, and ^piq Ir-Cz.

HOMO and LUMO energy levels of the iridium polymer were measured through the CV and the starting point of the absorption spectrum.

Referring to FIG. 12, the two materials had similar HOMO levels (˜5.10 eV) but the LUMO levels were higher for iridium polymers with triphenylamine units than for iridium polymers with carbazole units. Therefore, electrons are more easily injected into the light emitting layer in the iridium polymer having triphenylamine units than the iridium polymer with the carbazole unit, which balances electrons and holes in the light emitting layer, thereby increasing the efficiency of the device. In addition, when PPV or PEDOT was used as the hole injection layer, the hole flow was too fast. For this reason, an electron and hole imbalance occurred between the light emitting layers, resulting in a decrease in device efficiency.

While the embodiments of the present invention have been described above, it will be understood by those skilled in the art that the present invention may be implemented in other specific forms without changing the technical spirit or essential features thereof.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

1 is a graph showing ultraviolet-visible light absorption spectra of wavelengths in the solid state of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA and ^piq Ir-Cz.

Figure 2 is a graph showing the ultraviolet-visible absorption spectrum according to the wavelength of the monomers, ^ppy Ir-BP, ^ppy Ir-BP in chloroform.

Figure 3 is a graph showing the emission spectrum in the solid state of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA and ^piq Ir-Cz.

4 is a graph showing the change in weight with temperature as a result of thermal analysis of BP-TPA, ^ppy Ir-TPA and ^ppy Ir-Cz.

5 is a graph showing current density according to voltage and luminance according to voltage in an organic electroluminescent device.

6 is a graph showing the external quantum efficiency according to the current density of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA and ^piq Ir-Cz.

7 is a graph showing the external quantum efficiency of PLEDs containing ^ppy Ir-TPA and ^piq Ir-TPA and using PPV as the hole injection layer.

FIG. 8 is a graph showing the external quantum efficiency of a PLED including ^ppy Ir-Cz and ^piq Ir-Cz and using PEDOT as a hole injection layer.

9 is a graph showing electroluminescence spectra of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA, and ^piq Ir-Cz.

10 is a graph showing color coordinates of each polymer on an organic electroluminescent device.

11 is a graph showing cyclic voltage current values of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA, and ^piq Ir-Cz.

12 is a graph showing electron energy of ^ppy Ir-TPA, ^ppy Ir-Cz, ^piq Ir-TPA, and ^piq Ir-Cz.

Claims (6)

A phosphorescent polymer represented by the following formula (1) or (2). [Formula 1]

(Wherein R is

or

to be.) [Formula 2]

(Wherein R is

or

to be.) delete delete delete delete An organic electroluminescent device having a light emitting layer comprising the phosphorescent polymer according to claim 1.

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